You take your eyes off your sails, your course, and your crew during a critical maneuver.
No thank you.
I'm rarely in a situation where a tack is a "critical maneuver". Even when it felt "critical" (crossing situation, shoaling bottom, something like that), it never felt like I had to keep an eye on the sails and crew and course continuously. I'm not sure that's even possible.
In any case
- I trust my crew to do their jobs or communicate with me when they can't.
- There's lots of other input from the sails besides visual (listen for luffing, watch the sheets).
- My boat rarely moves more than 10 ft/sec, so while switching sides using any method, the boat will probably not move more than one boatlength.
I guess if we're talking about a race where boats are packed in close, I could see it being dangerous to face aft while tacking. But actually I think that more serious than facing aft is the possibility of momentarily being disoriented. Imagine I'm on the port tack, we tack, and as I turn right and aft to switch to the other side I see another boat coming up fast over my right shoulder and we're tacking into his path. It might not be obvious in a split second what I need to do to avoid a collision (answer: should not have tacked in the first place), plus now I'm delayed if I have to reorient myself (he was over my right shoulder before but now he's over my left shoulder). You get the idea.
But this is a situation I'm very rarely in.