It's not that big of an issue. The Switch's screen is glass, and is therefore fairly resistant to scratching. It is considerably more resistant than the DS line of handhelds, which all had pressure-sensitive plastic screens. (and ABSOLUTELY needed screen protectors) There's also the reduced need for touching the screen. I'm sure there will be more games in the future that utilize the touchscreen more extensively, but for now it's not that big a deal.
One thing I notice is that the touchscreen on the Switch has a texture that makes it a bit more difficult to swipe your finger across it smoothly. For most games this isn't an issue, as poking at the screen works just fine. But I could see it becoming a problem with Fruit-Ninja style games. I'm going ahead with the tempered glass screen protector I ordered. The one I got for my smartphone looks and feels great. It is crystal clear and has a silky-smooth texture that makes it very easy to touch the screen. I wouldn't mind having something like that on my Switch. Scratches and damage to a screen protector is easily remedied. Scratches and damage to the unit itself is quite a bit more costly to address. That's why I usually employ screen protectors. That, and the fact that I collect these systems and love to have them in pristine condition, even after years of use.