To me the Russian grip is not a belt grip per say
like this you mean?

but I guess if you can reach down to the belt all the better
Osotogari, HArai Goshi, Soto MAkikomi and dif sacrifice throws are great from this position, sacrifice throws that easily follows thru into mount position,
I also like to just grip the belt on the side that you would grip the lapel, gives alotta oppurtunity to power moves