Is Slack’s Multi Login Design Good for UX?

From a user experience standpoint, does it hurt that a user that is part of multiple teams on Slack, is required to log in to each of them individually, and to type in each team's url/name individually? As opposed to going to one site, logging in once, and accessing any/all of their teams.

I understand the benefits in their architecture from a technical standpoint; however, for me as a user this seems counter intuitive.

Are there any studies or evidence in general that are in favor of, or against this type of user flow?