Yes, the contractions during orgasm are basically kegels, so it will help improve things slightly, but only so much as doing a few seconds of kegels will...it's not nearly enough to make a real difference unless you're having 25 orgasms a day.
Exercising the pelvic floor muscles improves orgasm for a few reasons. -The stronger the muscle the more nerve endings.
-The stronger the muscle the more powerful the contractions are during orgasm.
-Exercise improves circulation and the better the circulation down there the more sensitive the clitoris becomes. Doing kegels before or during sex increases blood flow to the area, which will help things along.
-For many women squeezing the muscles during sex or masturbation increases arousal and helps bring on an orgasm. If the pelvic floor is weak, this may not be possible or won't have much of an effect.
And yes, the more you do it the more you'll want it. Partly because once you get stuck in the rut of not having sex, it's easy to see minor inconveniences as huge barriers preventing you from having sex. Whereas if you're having sex regularly you know it's possible to find the time because you've already managed it 3 times this week.