If you want to really study how a state works, than you need control to go in and out of the state.

If you want to research how a certain mental state leads the body to produce additional warmth than it's highly useful to be able to have control to go in and out of the state by conscious decision.

Researching the mind isn't easy. You don't see very well what the human mind does through putting people into an fMRI. Having awareness of what happens in your own mind is a good way to understand minds better.

Of course you can also learn something through experiments but it's often hard to know from reading a scientific paper in which state the participants have been during the experiment. A lot of psychology experiments are also not well replicated so you don't really know which effects are stable and which aren't.

People who are not aware of what happens in their own mind also frequently project their own issues into other people. That makes it hard to understand why other people do what they do. Meditation helps you to become aware of the stuff that happens inside your own mind.