On the contrary, if there are simultaneous turns(which you have if there are two companions beside each other), Its useful in multiplayer if you know that your companion is preparing a spell, or a dash, or a skill... before moving yourself. And if they have a "channeling" animation you know he/she`s going to do something.
It's useful to know when a team member has actually done something, but if you are flitting between possible options the way Swen was playing the game, maybe less so? I suppose it depends on what other shared communications you have.
You would also have to be viewing the same world-space as your team-mate to see what their avatar is doing, which is not forced on you in BG3. I wasn't looking for MP hints, so I didn't notice if the potential activities were reflected elswwhere in the UI; the portraits would be an obvious place to show status and activity, I suppose.
