Bots AntiSpam in telegram

Recently I have been visiting quite a few groups on telegram, I have seen in many, almost all of which use the same bot.

The method is to use captchas or polls for the user to check if it is real or not. To be honest, it's quite effective. If you have a community that you want to protect.

I was so interested in this because it is something quite new for me since it is one more way to protect groups.

I would like to know if this could be profitable? I mean, build this and sell it? Or rent it monthly?

Would it be a good way to earn money?

I read your post.