yes but there are alot of people out there that don't know exactly what kind of tone they want, so they get an amp that can do all of them before figuring out which kind of amp to get... now, an amp model of a particular amp won't sound as good as the real thing, but it'll give you the gist of it. also, some people want more then one tone, without having to buy several guitars and amps. thus, an all-in-one amp suits them.

it makes for a good practice amp... I wouldn't use one for gigging (ok, that's a lie, because I do use my spider II for gigging, but only because it's the only amp I have at the moment!) but if I were to go professional, or at least get together with a real band to play a gig for 100+ people that I've never met before, then yes, I would go with a non-modelling amp.

you've been playing for a long time lord, and have had lots of different kinds of gear over the years. so you probably already know what kind of tone you want by now. however, some people don't fully know what they want, and they need something that can do everything, though not perfectly, to decide upon which things they use the most, and what they can do without. this is also why I recommend multi-fx pedals to beginners. it helped me, for example, I now know that I love chorus, and never use tremolo or pitch shifter, and very rarely flanger. thus, I know what single pedals to buy... it's like this, except with amps, not pedals. for example, I find myself using a good crunch more then a light overdrive or super high gain setting for most applications, therefore, I know I'll probably want an amp that gives a good crunch sound, so I know that I probably won't want a mesa... does this make sense at all to you?