This is a good question.
The first problem with the Advaita interpretation is that Advaita Brahman is not an ocean since it is not an object. There is no second entity. So who is seeing the Advaita Brahman as an ocean?
Manu said, ‘Brahma is not an object of touch, or of hearing, or of
taste, or of sight, or of smell, or of any deductive inference from
the Known. Only the Understanding (when withdrawn from everything
else) can attain to it. All objects that the mind apprehends through
the senses are capable of being withdrawn into the mind; the mind can
be withdrawn into the understanding; the Understanding can be
withdrawn into the soul, and the Soul into the Supreme.’
Mahabharata, Santi Parva, Section CCIV
The second problem is that Maya is inexplicable and unknowable in the Advaita scheme and can't be compared to a wave.
From the point of view of Advaita Vedanta, maya and avidya are the
same. Just as avidya or ignorance has the powers, as it were, to hide
Brahman and project something else, such as the world, on it, so also
maya, as it were, can cover up Brahman and project the world onto it.
Maya cannot really cover the Reality that is Brahman. A patch of cloud
can never cover the sun. It only covers the eyes of those who are
looking at the sun. In the same way maya covers our knowing ability
and thus obstructs our knowledge of Brahman. In any act of knowing,
the ‘knower’ and the object known’ have to be separate from each
other. They cannot be the same. In order for us to know maya, it has
to be separate from us. Individuals like us are the products of maya
and we are all posited within the domain of maya. Maya and we
individuals are not separate from each other, just as chocolate and a
bear-shaped chocolate candy are not different from each other. As we
are identical with maya, we cannot know maya. For this reason, maya is
not only unknowable; it is inexplicable as well (anirvachaniya).
Journey from Many to One essentials of Advaita Vedanta by Swami Bhaskarananda
The illustration of the ocean with its waves is really a Kashmiri Saivism interpretation and not in accord with Advaita Vedanta.
So the question boils down to why Advaitins use a Kashmiri Saivism style interpretation?
The reason is that there is no way to explain Maya in Advaita Vedanta. Yet this maya is necessary to explain the universe given that the Advaita Brahman is inert.
Ultimate Reality is cit or Parasamvit. It is non-relational
consciousness. It is the changeless principle of all changes. In it,
there is no distinction of subject and object, of I and This. It is
the Supreme Self surveying Itself. In the words of Pratyabhijna
Sastra, it is prakasa-vimarsamaya. Prakasa is the eternal light
without which nothing can appear. It is Siva. Vimarsa is Sakti, the
swabhava of Siva. It is, so to speak, the mirror in which Siva
realizes His own grandeur, power and beauty. Vimarsa is the Katrtva
Sakti (the power of doership) of Siva.
Mere Prakasa cannot be the nature of Reality. Even diamond is prakasa,
but the diamond does not know itself as prakasa. Vimarsa is that
aspect of prakasa by which it knows itself. That self knowledge is
Vimarsa betokens that activity. As Ksemraja says in his Parapravesika
(p. 2), Vimarsa is "akrtrimaham iti visphuranam". It is the
non-relational, immediate awareness of I. Ksemraja says, "Yadi
nirvimarsah syat anisvaro judasca prasajyeta" (Parapravesika, p.2)
i.e. "If Ultimate Reality were merely prakasa and not also vimarsa, it
would be entirely powerless and inert." It is this I-consciousness of
Ultimate Reality that is responsible for the manifestation,
maintenance, and reabsorption of the universe.
Cit is conscious of itself as Cidrupini Sakti. This consciousness of
itself as Cidrupini sakti is Vimarsa. ....
It is because Sankara Vedanta considers Brahman to be only prakasa or
jnana (light or illumination) without any vimarsa or activity that it
has to invoke the help of Maya for the manifestation of the universe.
Brahman is devoid of any activity; it is, therefore, impotent to
create. It is, only Isvara or mayopahita caitanya that can manifest
the universe. But whence does this maya drop in? If it is some power
extraneous to Brahman or Isvara, then Sankara Vedanta is reduced to
dualism. If Maya is only an expression of the power of Brahman, then
Brahman cannot be devoid of activity. Both Sankhya and Vedanta
consider the Purusa or Atma to be niskriya or inactive, because they
take the word 'activity' in a very crude sense. Surely, Brahman or
Atma does not work like a potter or watch-maker. The very Vimarsa, the
very Iccha (will) of the Divine is spiritual energy of incalculable
force that can penetrate into any form from the subtlest to the
Ultimate Reality is not only Universal Consciousness but also Supreme
spiritual energy or power. This All-inclusive Universal Consciousness,
is also called Anuttara, the Highest Reality, the Absolute. It is both
transcendental (visvottirna) and immanent (visvamaya).
It is the svabhava or very nature of Ultimate Reality to manifest.
Creativity is of the very essence of Divinity. If the Ultimate Reality
did not manifest, then it would not be Self or consciousness, but
not-Self, something like a jar.......
Introduction to Siva Sutras by Jaidev Singh