OVFs like the Tele-Wide can be had cheaply and don't take up a lot of space in the kit bag, so I think they are a useful backup plan. With a little practice, you can get a feel for how various focal lengths match up to the markings in the OVF.
I've had numerous occasions with my dSLRs (K-x, etc.) where the sun was at just the wrong angle, rendering the regular viewfinder useless, but I worked through it, and no one complains because Pentax didn't provide a bag to put over your head for those times.
I honestly think it's the "different" factor that drives the discussion more than the actual problem.
I'm still shopping for one of the KMZ 'turret'-type finders, more than anything else because I think they look cool.
Apparently, the average price is exactly one dollar more than my top bid, whatever that may be (friggin' snipers...)