I don’t have it but I’ve seen admin/dev comments on this, with 1.0 release they plan to add offline singleplayer, and currently online is required on character select/launch, but losing internet connection during play will not kick you out or interrupt it.

I’m keeping my eye on it and will probably pick it up when offline singleplayer is added, but that being included is the deciding factor on if I’ll get it or not myself, since it’s just a promise for now and those can be broken.

Edit: apparently its already added according to other replies