This is very old technique and these days you can not make big money with this. House will catch you and will ban you from their casino. Even you will end up beaten by them badly.
This is a highly possible scenario in a physical casino that you will be beaten up for counting the cards and only in movies i have seen these kind of scenarios but i a virtual casino the house knows the situation and there will be a timer to counter that, not sure what is the solution they are using but these virtual casino will be aware of the thing and will have a solution to counter those.