No, No. A winning player avg 1BB/hour over a long period goes on a hot streak averaging 10BB/hour for a short period should expect a win rate of 1BB/hour for the next hour. Similarly if he averages a loss of 1BB/hour for a short hour should expect a win rate of 1BB/hour for the next hour.

Regression to the mean occurs when the two variables have some positive correlation. Here the two variables are two separate time slots (the last hours and the next hour) there is no statistical correlation of the results between these two time periods, hence the best guess for the next hour is the Mean.

Regression to the mean is misused in this context.