MLS,
Logging IFR time just to make a visual approach is fair game when the rules one was complying to were the old Danish rules which required 20hrs IFR per year to remain current. If you don't know how much IFR time you're going to get in the next 12 months you start by taking every opportunity to log IFR. Wasn't a problem as it turned out but nevertheless a good way to begin to get comfortable with 'the system', controller relations and such like.
tmmorris
When one flies commercially there are other considerations. It is totally impractical, not to mention unrealistic, to log actual 'sole reference' time.
Also, due to the shape and size of the aircraft cockpit, flight by sole reference to the instruments is almost always what one is actually doing.
If one should choose to look out of the window and the bank angle increases to more than 30 degrees(or whatever your book says) some-one(PNF) will poke you on the shoulder. Then you'll look back at the AH and correct the situation. Same for navigational inaccuracy.
Like Chuck says, the outside world can be a distraction.