Play Strategy vs. Bet Variation

Hi, I have a simple question: Since bet variation is so under heat, why don't people just use some counting system that is more efficient in play strategy? Then they can win without bet variation. These can be done especially in SD or DD.

You don't need to worry about pit boss any more. Any you don't have to wait for the juicy pack. With proper strategy, you can take adavantage whatever the count is.

But there doesn't seem to a lot people doing this. Anything wrong with this?