Humans do not only do things because they "make sense" / "scientifically proven", many times we just do it because its low effort and helps make other people feel comfortable.
Its like smiling when you see a stranger, or saying good morning to someone. There is no sense to it, you don't plan to stop and chat. However, it breeds a comfort (and eventually a distant camaraderie) because a greeting means a lot to them. Typically a greeting signals (sometimes falsely) a lack of malicious intent.
Given they are a team all sitting in the same room, even if one of them is more comfortable with masks on (logically or illogically), its just a kind thing to do for each other. Much like choosing to keep your cellphone off in a theatre, choosing not to smoke while in a group on non-smokers (outdoors or indoors), choosing to let everyone else exit an elevator before you, or choosing to respond to a comment you know is likely better left ignored :).
I wish you the best of luck in the future, and hope (masks or no masks - whatever strategy to help others you choose to use) you use some small amount of your time/effort to help make other people's lives a bit more comfortable.