I would actually really appreciate a bot that does that. There are so many bandges which are broken which is just annoying and many maintainers do not care about the readme once they have written it. They do accept pull requests but don’t update it manually.

And since the bot is only creating pull requests, I don’t see any harm: worst case for my repo, it would brake the readme but I double check it just like any other pull request, realize that it messed up, and fix it myself (but I would be thankful the bot noticed the broken link and I have a motivation to fix it).

What is a bit problematic about this bot would be that, due to a bug, it starts spamming (creating 1000 of pull requests) flagging false positives, etc).

Furthermore, it is also important where to draw the line. A bot that notices something is broken and offers me a fix is ok. A bot that notices I use a working service X and offers a pull requests to use service Y could be problematic because it might be useful but might also be annoying (because it is advertising, and service X might be good enough for me.