It certainly helps your acting, but I wouldn't call it the base. Films and plays don't require improv,but it makes the bloopers funny. :). There are a couple of directors who use imrpov to make an entire film, but that is pretty uncommon.
Actually, thinking of it, before most people begin to act seriously/professionally, they do use improv. It kind of builds you up for the 'real' thing, so yeah, you could call it a base I guess.
Grr I'm confusing myself. I changed my opinion halfway through my answer. Hopefully you can make some sense of it.
Is it theee base? I don't believe so, is it important and a good place to go if you're starting out? I would think so. Improv does help your acting, you need to be able to think on your feet-and well act. You need originality, and need to be able to show your personality. It's not hard to lose yourself with acting, and I believe that improv is a good way to show, and preserve who you are. It's another way to express yourself.
do you mean improvise then yes or improve you need togo to a theatre or an acting class