generally for the top wrestler its more advantageous to have less space between the bottom wrestler in traditional referees position (one knee down).

Usually the optional standing start is used when the top wrestler wants to "give" an escape ("cutting the bottom guy free") but make the bottom man exert some energy, possibly make a mistake, and keep him guessing.

When the bottom man has the top man doing an optional standing start, if he can hit a full speed standup going forward there's no reason he shouldn't get to his feet. Occasionally the top man does something actually offensive from the optional standing start like a cradle, but that usually is the result of the bottom man hesitating and that's incredibly rare at the high levels like NCAA D1.