It captures the nature of summons being powerful effects as they are in the game, but they can only exist temporarily
Once per turn, when creatures with counters on them deal combat damage to a player, the player who controls Tidus can draw a card and proliferate (i.e., add an extra counter to creatures and permanents that already have them)
Just playing her as a 3/7 that demands an answer, while bouncing something back to hand for you to ink or get value with later is going to be good enough much of the time
With Belle's House, you can make the most of the inventor's innovations
The average green commander deck will likely play a mix of 2mv and 3mv ramp, with maybe one or two more expensive ramp cards
Sephiroth, One-Winged Angel also becomes a much more potent sacrifice outlet, and one that is harder to block in combat