In most circumstances, I feel like using metaclasses is a red flag. How many people are there on earth who understand and regularly use meta classes when they're appropriate? I always pegged metaclasses as "you should know this exists in case you ever get unlucky enough to need it but otherwise stay the hell away from it"
I agree with you in that it's nice to know that metaclasses exist, and that you can potentially reach for them in a pinch.
I also think you can go really far in Python development without ever needing to know about metaclasses.
I once used metaclasses because I was writing a code generator for a DSL. But that was the only time.
Conceptually they're not too difficult but more likely than not YAGNI.
The worst thing about metaclass is that 95% of python programmers look at it and just go "whuzzat?" and require a seminar to catch a clue. It's actively hostile to whoever maintains the code after you.