I have never, even as a guest liked the way Booking.com score reviews. When reviewing as a guest, sometimes I do not want to give a 10 but I'm not prepared to drop to 7.5. If you have to drop by 25% each time then scores should only be 1 to 5.
However, now as an advertiser, I like it even less that guests can score each section and then give an overall score. Recently I have received 10 for all sections but an overall score of 8 and 9. Only the 8 and 9 score show and are logged as such. It wouldn't be so bad if the potential guests could see how each section was scored but the can't they only see the overall score.
The review score is supposed to be improved, I think it just got worse.