Now the question is of course, is this really necessary? I mean, if you accidentally moved a channel, you can always just move it back if required - or are there any issues with that which I'm not aware of?

Apart from the inconvenience of trying to find a channel that has been moved from where i expect it to be, or moving all the data from a channel i didn't want to write into with the data, i wouldn't say it's "necessary." When i begin placing notes into a channel which i presume to be my target channel (because i name my channels in a series, such as Synth 1a - Synth 1b - Synth 2a - Synth 2b, etc, or when i'm using channels for piano notes or guitar strings, and naming the channels as such: C4 - G4 - D5 - A5 - D6 - F#6), then i realize i've put several patterns of data in the wrong channel because it wasn't in the position i intended it to be, i have to go back and move the data i entered into the wrong channel to the one i intended it it to be in, then for the sake of my production, move the channel to the correct position.
Sometimes this can have serious effects, as many commands, like SFX apply to that channel only.
Like almost all FRs, it's simply a matter of productive convenience. In this case, we want to avoid creating problems accidentally. Like i've said elsewhere, wasting time can kill an inspiration.

I see your point, and I don't see your point at the same time, probably because I never had any issues with accidentally moved channels (I did accidentally move channels a few times and didn't even notice). However, I think what would help even more in the situation you describe are channel groups. If all the channels belonging to the same synth would be in the same group, you simply couldn't accidentally drag one channel out of the group anymore and everything would stay bundled in one place.