So now you're sitting there as a VFR Pilot who has inadvertently entered IMC thinking "S**t, S**t, S**t, I need to get out of here, umm, ok, turn onto reciprocal heading ummm...TAS is ummm... I'm going 120kts i'm at 2500ft so take that, divide by 1000, 2.5, times that by 2 ...no wait, 4, no 5 that's right, damn, haven't done this in a while... ok so that is 12.5 add that to 120 so about 132, now divide that by 10...umm... 13 add 7, 20 degrees, ok, damn, there is no 20 degree marking on my AH, just 15, 30, 45, ok, so just 15 plus a little extra I guess...sure, that looks about right...ok, now time it for the next minute..." Theres an extra 30 seconds worth of IMC you now have to turn back around and get out of so an extra minute assuming you were pretty accurate in your working out and got your heading correct and aren't heading out further into muck, that's a fair whack of your 178seconds CASA reckons you have left to live!
Or, I could go ""S**t, S**t, S**t, I need to get out of here, umm, ok, rate one turn, ok, now time it for the next minute..."
Now you tell me which of those 2 scenarios looks easier? Once again remembering that you're in IMC in a VFR Aircraft relying on an AH you don't really spend a lot of time paying attention to assuming that it's working correctly and isn't slowly toppling sending you into a spiral dive or isn't a bit lazy meaning you roll out at say 160degrees instead of 180, and yes you have you're DG and you can compare to that but once again you'd need to correct it because if it's like most DGs out there it's probably gone out by a reasonable amount during the turn and if you're in IMC you're stupid little Mag Compass is now bouncing around making it harder to get an accurate reading to reset your DG....
That T+B, if it's working, it's working, end of story. Getting out of IMC in a VFR Aircraft that'd be what I would teach someone to do and it's what I was taught to do as well, the AH becomes your backup to confirm, not the other way around. Plus teaching a VFR Pilot they'll be better off using the AH could lead them to a false thought of "Well, I'm already in it and I can use this AH so I'll just continue on" instead of "Nope, never really been advised to use AH before, not comfortable with that, I'll just got with the T+B to turn around and get the hell out!"
Yeah, I know, I'm looking at worst case scenarios but I'd rather assume the worst and be pleasantly surprised than the other way around!