Yes it is worth it! I think what you are others on this forum, and of course others who are not on this forum do for cats is just wonderful. I am in awe of all of you who give you time and effort to take care of cats the way you do.
It's worth it knowing that these cats are getting looked after and are not being let to run wild and have loads of unwanted kittens.
I think what you all do is just great, keep up the good work, even if it gets hard, inevitably everything is hard at the time, but looking back you'll be so so glad you've done it.