Lower visibility. Out of sight, out of mind. Even in small companies (ranging from 5 to approx. 20 people) I still felt like a number most of the time, like I didn't have much say in the company.
It also does a number on your soft skills if you don't get out much. I noticed a sharp decrease in job offer rate for job interviews before and after my first job in a remote team for 2 years. But other factors might have also been at play at the change in offer rate.