Can't you easily accomplish this using their teams feature? I just set up a team and add the appropriate users with the right permissions for the team's boards.
Lets say I am a personal user, and share some boards with family and friends. Now you want to add me to a team for work. You won't be able to find me using my work email address - instead you'll have to map in whatever random service I use for personal email. Let's hope my personal identity doesn't conflict with work.
Now I am team member and can also access boards. That also means that team boards are exposed whenever and wherever I login, even if I only want to login for personal information. Some family members and friends may know my personal login, so now team information is also accessible to them.
I'll now get notifications for personal and work related activity going to the same browsers and email accounts. Are you sure work's admin really wants work information going to my personal email account? Do I want to get distracted by personal notifications during a work day and vice versa?
Now that my personal and work are intermingled, I am also more likely to make a mistake such as creating new boards/lists/cards in the "wrong" place, and it will be harder to notice. Work can't be sure that they have everything backed up.
Then a year later I leave. Somehow the work admin is going to have to figure out which user I am (remember not related to work conventions and standards), and disentangle me. Providing I have been perfect and never intermingled anything, it will be fine. The odds of that are low.
Essentially the single account has just made everything worse, to the benefit of no-one.
Now I am team member and can also access boards. That also means that team boards are exposed whenever and wherever I login, even if I only want to login for personal information. Some family members and friends may know my personal login, so now team information is also accessible to them.
I'll now get notifications for personal and work related activity going to the same browsers and email accounts. Are you sure work's admin really wants work information going to my personal email account? Do I want to get distracted by personal notifications during a work day and vice versa?
Now that my personal and work are intermingled, I am also more likely to make a mistake such as creating new boards/lists/cards in the "wrong" place, and it will be harder to notice. Work can't be sure that they have everything backed up.
Then a year later I leave. Somehow the work admin is going to have to figure out which user I am (remember not related to work conventions and standards), and disentangle me. Providing I have been perfect and never intermingled anything, it will be fine. The odds of that are low.
Essentially the single account has just made everything worse, to the benefit of no-one.