Sure.

However, assuming two exceptional employees rated consistently 7-10, there's a measurable difference between an 8.2 and an 8.6.

The alternative is 3 vs. 3.

People also like to have options. Having a sad face, a neutral face and a smiley doesn't really cut it for pretty much anything.

Having the option of 1 being "utter shit" and 4 being "bad but workable" seems like it has benefits.