As I tend to think (I don't say that I'm 100% correct), if a card game is not against the house alone, i.e. there is more than one "human" player in the game, it should involve a certain amount of skill in the way poker does. So no matter what kind of game it is, it is not just pure luck, at least as long as human factor is involved
For example, you may not be lucky to get the best hand but you can bluff and still win in the end (you can either wait or force the pace). To put differently, it greatly depends on a particular implementation of such a game and if the interface allows things like bluffing (through chat or otherwise)
Online poker has a very unique advantage or disadvantage when it comes to bluffing. You cannot see the face,,, cannot see shaking hands, or twitching eyes or whatever, and you can even switch off chat and not let people see your words. But you can still see patterns very well. What players seem to do when cards are revealed, etc.
You can also as you say bluff more effectively, but online very difficult to see the effect of your words.