No.
Yes. I've tried it.
The building is either going to take you 6 years, or it's going to look like crap. See: Every one of those popular ROBLOX games built. They have minimal detail because detail would take ages.
The physics are crap. Not only is there no client sided collision, but you also fall when walking up stairs, and pretty well doing anything else.
With apperently 30 fps, the game still looks like a slideshow.
I don't insult the community, because every community has friends in it.