Rating systems are inherently flawed because everyone has a different idea of what 10 and 0 and even 5 mean. imo it would work well if we all agreed 10 = excellent, but not perfect (because nothing ever is), 5 = mediocre, but worth watching especially if you're into the genre, and 0 = terrible, not worth it no matter what. But often people equate it to grades in school so 10 = perfect, 9=great, 8= good, 7=passable, 6 = failing grade
Especially in non-professional* reviews, 10 point systems rarely use anything below 6. It's quite frustrating.
Words are by far better, but take a lot more time to produce and
consume. With number you can get aggregate scores (that mean nothing because people use the scale differently), that give you the average opinion.
As for the 'if you drop it you need to give it a low score' is flawed thinking.
I was really busy
from late last year up until a few weeks ago. I dropped lots of things I found passable just because I had limited time. Or just an inexplicable inability to jive with something in the show. Like me with Cowboy Bebop. I've got nothing in particular against the show, I just don't care. I don't think it's bad. I simply don't care enough to keep watching.