It was not just playing part of the game, like what usually happens in a demo. This was its own miniaturized look at the game as a bit of a side story we won't see in the game proper. It was a unique idea and not too bad, but it was really just too short to be that interesting. You can replay however many times you want - but really only doing it 10 is worthwhile to get all of the rewards that carry over to the main game (which is also a really cool thing). But the only part that actually mattered as the first visit and that just seemed awfully rushed and didn't interest me. If you had never played the original Ruby or Sapphire, I could totally understand being really confused by what was going on.
Steven bragging about his shiny Metagross and how he just so wishes he could give it to you was pretty funny though.
Ultimately this was for the special Pokémon and its Mega Stone, though. And Mega Glalie is awesome! (Though I do sincerely hope Steelix is still obtainable outside of Japan somewhere within the game itself... if not, that's pretty ridiculous.) So I do look forward to having him in my game heh.
I wasn't really looking forward to the demo, so maybe that's why I didn't care for it. We still don't even know if the stones for the special megas in them won't be obtainable normally, which would completely defeat the point of transferring from the demo. And I assume they will be, so I never saw the point of a demo. It's Pokémon, we know what the game is like.
I'm still looking forward to Omega Ruby, don't get me wrong. I played wayyyyy too much Y... I have fully trained almost too many Pokémon and even have plans never fulfilled. And I wore myself out... Doing an actual adventure again sounds great to me.
I still can't decide on which starter to choose, however... A big part of me doesn't want to do Blaziken again, especially when its Mega Evolution is one I've already used a fair bit, but I have always picked the Fire starter... Playing with all three in the demo didn't help any though since they all look cool lol.