It is a nice feature on DS and 3DS. Only 1 person have the game, and all your friends that have the console can play together the same game.

Switch is focused a lot in share the play by sharing the joy-con with a friend, but also in local multiplayer where 8 switches can conect together and play. But all switch owners must have the game? They didnt mentioned nothing about that. Can we assume we wont have this feature?

Would be a nice feature since the Switch has that appeal of local play and bringing it to play with friends.But if it will have it, your guess is just as good as mine.

It was a great feature that was used quite a lot for the NDS but really lacked for 3DS games.. I can only think of a few 3DS games that even have this feature, so I wouldn't count on this being on the Switch

Would be nice to have, though it depends on which games would utilize this feature

I think it depends on the games. Maybe games like Bomberman, Arms, 1 2 Switch,NBA, Fifa and the next Mario Party will allow download play without the owning the game.