Relative story points measure relative velocity. What they don't measure is an actual effort, nor quality, nor give any tangible estimates. It is usually not possible to compare between teams too. As you pointed out, can be easier abused.

I was actually a part of company where they decided to introduce bonus, based on % of achieved velocity. Our team was doing well before with above 90% accuracy, but we had teams at 70% and lower. After the bonus got introduced, magically all teams startered delivering 95%+. After one quarter the idea was scrapped and in my team we introduced non-relative points (as I described in the post).