I don't think that memorising cards is needed in poker. We won't really see the cards of our opponents, except of the table is being streamed online, that we could see other cards but this usually happens with a 5 to 30 minute delay. The only thing that we need is a poker strategy to play by, for that we will need to be able to calculate our chances of winning. This should be not so difficult if we don't multiple table many games. But since many people like to play fast online with many table at once, it makes more sense to create a chart for our hands we play with and our hands we fold. Such an strategy makes it very easy for us to decide which hands we want to focus on.
Each people will have their way to play poker so perhaps, memorizing cards will be one of many ways for them to win. Calculating the chances of winning is the other way to help us to win but not many of them can calculate with the right. We could miss the calculation if we don't have much experience playing poker card games.
It isn't easy but if you put your mind into something, there is a high chance that you can do it. Bluffing is an easy skill to learn but the problem is how can you make yourself look convincing, you have to look like you don't know a thing about bluffing and at the same time know about bluffing without the opponent knowing the latter.
Perhaps, I can try it someday, but I hope that will works for me since I don't much about poker cards. But I think I can bluff someone and make myself look convincing in front of them because I can do that in the other things
Pretend to be a newbie can the other way for us to trick another player, so they don't expect that we have skills to win the game. I think that can work for people who want to hide their skills in poker.