Each of the modes has an additional cost, similar to spree, but only one mode can be chosen when the spell is cast
While the upside of picking up a Town and gaining two life isnt huge, in a format dominated by Prowess, any life buffer is nice
You don't have to exert them (in fact, technically speaking, they're already turned on their side!), this is just a static ability
For 7, Cloud wielding a big sword lines up nicely with the equipment strategies of a white-red Magic deck, but Holt says that adding green to the mix let us tie in the power matters cards and cards that reference the Planet and lifestream. While Tidus ability to pass counters around might lead you to think the deck for 10 is all about Blitzball, this classic white-blue-green strategy actually primarily came from the idea of that games Sphere Grid leveling system as a way to empower your creatures
The idea works really well in just Izzet Blue/Red, but splashing some Black gives access to the mighty Kuja, Genome Sorcerer