In CS (which is admittedly quite different), one counterbalancing incentive is that citations are at least as important as coauthorships in recent years, and re

In CS (which is admittedly quite different), one counterbalancing incentive is that citations are at least as important as coauthorships in recent years, and releasing data is one relatively easy way to get a boost in citations. If you just release results, then people only cite your paper if they're doing particularly related work. But if you also release an accompanying dataset, all sorts of random people will cite this paper as the source of the data (if the data is interesting, anyway), even if they don't care about the paper itself.