It’s all based on preference to you and your usage. I like keeping my devices pristine, so I always put screen protectors on them to keep them nicer longer. I hate when I see scratches on the actual screen of the device so I prevent that from happening to the best of my ability. My 2018 11” iPad Pro has a screen protector and my Note 9 has a screen protector. I ordered an 11 Pro Max that will be coming in the mail on Monday and the first thing I’m doing before I even turn it on is put a screen protector. Now, the screens are durable to an extent where they can withstand daily life and not get as scratched up. I just like putting one on for a peace of mind.
Also, if you tend to drop your phone a lot, I would definitely recommend one as the protector will take the hit before it goes to the phone. In the end, it’s up to you!