It has its pros and cons, just like anything else.

For example, I do custom. PHPStorm is strongly geared towards popular frameworks.

Sometimes this autocomplete does really crazy things, like a function that I didn’t complete because it didn’t understand my custom syntax, for example, but then completed it to something very similar known from popular frameworks. This sometimes causes these “slightly blurred” autocompletes to me.

In addition, it sometimes messes up my syntax, or what it does sometimes very annoyingly is autocomplete when you want to type something in between. Unfortunately, it often doesn’t understand things when you want to auto-renew somewhere in between, but then leave out those last letters.

Often what breaks my stop is pointlessness, eg “non-existent class calls” or “non-existent variables” that do exist, but are incomprehensible, so I have to turn off error checking entirely because it’s just annoying shit.

There is also a super typical irritation with “braces”. For example, I name a variable, but phpstorm automatically converts it into a function by adding () after it.
Or I want to post a single quote, but PHPStorm automatically makes it two quotes, it also deletes them when I hit delete/backspace, so that I first have to go somewhere and go back to one just to remove the 2.

These are just a few examples of situational irritation. Obviously, that’s a huge 50-50 ratio, because now it’s on and then these irritations can be noticed. If it were turned off, I can also guarantee that I would miss auto-renew in a big way.
It just can’t read your mind and it doesn’t work perfectly. It’s “usually” great, but it can be terribly annoying depending on the specific situation.

This doesn’t change the fact that I use an IDE specifically for this sort of thing, so I partially agree with you. Name only the less beautiful aspects.
This is my statement and you have to be content with it.