Greater risk they could spread virus to others I suppose?
I guess my biggest gripe with those who can get vaccinated and do not is looking at hospital ICUs. A vast majority around the world have unvaccinated individuals occupying those beds, giving less opportunity to treat others. Cancer, knee surgery, etc.
If you don't want to take one of the vaccines available, the traditional AstraZeneca formula, or the newer mRNA vaccines, fine. But waive your spot in ICU if it comes to that point, and please be wary of the immunocompromised.