Variance will remain the same. The 0.1% cash reward will just lessen the house edge by 0.1%. Almost all web casinos have such a promotion � comp points that can be converted to cash. But in online casinos you don�t stand a chance in a long run. Good cards!
let me take a example of loss rebate 10% evry hand, take a large value 4 easy undestanding, though it is not practical.
if win/loss is 50/50, suppose no sp/DD
occ. 0.5 x 1^2= 0.5 (win 1 pay 1)
occ. 0.5 x [(-0.9)^2] = 0.405 (lose 90%)
Var=0.905 in stead of V=1 for no rebate, reduce about 0.1