This is from Bhagavad-gita 17.4. This shloka talks about worship in different guna of material nature. But Ishvara, the Supreme Being, is said to be above the gunas of material nature, as said right in the previous shloka, in 7.13.
People who worship the Supreme Being do not get any siddhi, if Ishvara considers it unnecessary for their service. However, obviously, He can grant anything to the one worshiping Him.
The important difference is, relationship with the Supreme Lord is completely above the material world. If you depend on some material stuff, then He will give you that, be it siddhi (supernatural powers), kama (satisfaction of the senses) or artha (prosperity), but the goal of relationships with Him is complete detachment from anything material not related to the devotional service. It's not even moksha.
Worshipping the devas like Indra or Brahma or any other deva can benefit you in the area covered by this deva, but those blessings will stay within the material world, meaning, they'll end when you inevitably die.