amps with multiple inputs

so in my amp shopping/searching/researching i've noticed that a few amps feature multiple inputs. i am not talking about amps such as a fender FM-212 that have inputs for multiple instruments. i am talking about a few VOX, mesa/boogie, and today i saw a bugera V-22 that have two different inputs.

for instance in the vox amp (i think it was an AC15 reactor?), there is a "normal" input, and a "top boost" input. the concept is that each input is for a different sound.

my question is --- what is the purpose of this? does this mean you have to physically change inputs if you want to switch to the other sound? how is this better than an amp with two (or more) foot-switchable channels?

i thought that AC15 looked like a decent amp, but i'm really turned off by the necessity of having to unplug/replug my instument into a different input each time i want to change tone. my main goal is to get a footswitch to instantly switch from clean to driven sounds.

Most higher end amps(bigger ones too) will have a High and Low gain input, some have 2, others(like Marshall) had 4.

However if you want to go from dirty to clean, that's not the purpose of the different inputs, that's the purpose of a multichannel amp.
The inputs are only going to make so much of a difference.

Though another good route would be to buy a good overdrive/distortion pedal and run that through the clean channel on the amp.

My amp has two inputs.
Labeled input 1, Input 2.
One is for higher power, one for lower power.
Which is which was lost a long time ago.
End result isn't very noticible.

Don't try putting multible guitars in one amp though. Lower power input will get drowned out.

My guitar teacher had one with two inputs and we played two guitars at the same time and it sounded great. he also said that that amp was about 1500 dollars when he got it. so I guess it all depend on the amp model.

most amps with a high/low input will actually run 2 guitars at the same time. it's definitely not something that should be done all the time but they will usually revert to being low gain inputs when they get used. At least that's what one of my older amps did.