are microservices really a good idea?

i may have missed something, but here is how i see it:

the default is "just call a function". it's fast, simple, safe, easy to follow. with microservices, you can no longer "just do it".

• you're forced to add a communication layer
• handle failures, decide on a retry logic
• "find usages" no longer works, the code becomes harder to understand, the execution flow becomes unclear
• you re-implement common logic/data classes as opposed to just using them as you would in a mono-repo approach.

so here is my question:

why not use a mono-repo instead, with an identical structure except that everything is easier because there's no "in another repo"-barrier? what prevents us from implementing different services in the same repo, getting the advantages of both worlds?