Generally these limits exist so customers don’t accidentally spend more than they intend to — e.g. implementing a sort of infinite loop where Lambdas call each other constantly. Sounds implausible but I’ve seen that more than once!
The textbook example of this going wrong is a lambda that is invoked on uploading to S3 that writes the result to S3. There's even an AWS article on it - [0]
[0] https://aws.amazon.com/blogs/compute/avoiding-recursive-invo...