This is strictly useful in Centur-Ion Decks, despite having generic Synchro Material requirements
So I would run something like a 3-1-1-2 line, with three Eevee, one Jolteon, one Vaporeon, two Flareons, or something like that
They have systems watching retailer inventory around the clock and alerting them the moment products become available
As for Suicunes damage potential, it will really depend on the development of the game
The ability to copy each subsequent spell on the other half is nice, but we already have less convoluted ways to achieve the same resultachieve the same result, and 7 defense is a lot to go through
If the permanent that was turned face up is no longer on the battlefield when Sumala Sentry's triggered ability resolves, you'll still put a +1/+1 counter on Sumala Sentry