It totally depends on whether you are watching a live dealer or simply at the mercy of an automated algorithm. If it's a live dealer, you could theoretically do card counting if you know the amount of decks involved and the shuffling mechanism allows it. There is absolutely no point in trying to beat the casino if it is a computer based random number generator because it will be manipulated to take away any possible advantage the player might get. Online casinos, like physical locations, are around to make profit for the owners - so they will take every step they can to ensure that happens.
I have done some reading about statistics of winning with card counting in live dealer versus pure online. No doubt that you can do it in live dealer compared to online where the time you spent is not worth the profit because it is very low. Plus you really need to be skilled in card counting and not just occasional player to pull off those statistics.