Its activated ability, which costs and the lives of three other creatures, exiles it and immediately returns it to the battlefield transformed
Barrenton Medic can prevent all damage that would be dealt to you and permanents you control, and Cinderhaze Witch can force your opponents to discard every card in their hands
Appa, Steadfast Guardian Appa, Steadfast Guardian is a big flying and blinking ally
It also works on artifacts, so you can have crazy charge counter synergies going on the Everflowing Chalices of this world
Better yet, casting two or more non-creature spells (which you'll likely be doing already anyway) gives Lyse Hext double strike, meaning you'll be dealing double damage with any attacks on top of whatever effects come from the non-creature spells you've been casting (which, again, are cheaper thanks to Lyse Hext's signature ability)