Yes. Google's spam filter is one of the best there is. It's possible to train a better bespoke one if you control your own email, but provide one for free for all your users? Nobody's ever done that better. And just imagine the amount of spam and grift that hits Gmail on the whole.

I remember the time before learning filters (turn of the 2000s). It was hopeless. (I also remember the time before spam email. It was hopeful.)