I think it could be very good as long as you can learn the lines, and that's not really all that hard once you get going. I get a lot out of singing, which has the same kind of tight structuring - introducing the songs without a script is much harder than the singing itself, and people used to say they were amazed I could sing so well given my talking voice. Since then I've tried harder to project and animate my speaking voice better, and the singing experience really helps that, because it means my voice is already trained to project itself.
A lot depends on the other people. But there's a common purpose, lots of co-operation and people depending on each other. Doing a play really brought the members of my first youth club together, and I got my first girlfriend because of it. One of the girls in the audience must have thought I looked good.
The task of doing the play gave me something to do, that was very important because on the ordinary social nights I just didn't know what to do or say, so I'd end up making an idiot of myself.