There are two views I've come across so far. They are contradictory, yet I find both of them reasonable given proper explanations.
Quote from an answer on Quora
these temples are located strategically at a place where the positive energy is abundantly available from the magnetic and electric wave distributions of north/south pole thrust. The main idol is placed in the core center of the temple, known as “Garbhagriha” or Moolasthanam. In fact, the temple structure is built after the idol has been placed. This Moolasthanam is where earth’s magnetic waves are found to be maximum. We know that there are some copper plates, inscribed with Vedic scripts, buried beneath the Main Idol. What are they really? No, they are not God’s / priests’ flash cards when they forget the shlokas. The copper plate absorbs earth’s magnetic waves and radiates it to the surroundings. Thus a person regularly visiting a temple and walking clockwise around the Main Idol receives the beamed magnetic waves and his body absorbs it. This is a very slow process and a regular visit will let him absorb more of this positive energy. Scientifically, it is the positive energy that we all require to have a healthy life.
Quote from a myth debunking website Nirmukta
This also explains why men are not allowed to wear shirts at a few temples and women are requested to wear more ornaments during temple visits.
Why? Should only the men benefit and not the women? Once again goes to
show how all religions are misogynistic to the core. In all
probability the men are basically forced to be bare-chested so that
they could identify who are all wearing the sacred thread and who are
not. Nothing but organized, divinely codified and sanctioned
I'll leave it up to you to decide what you choose to believe!