Best use of Gems

[Ginxt]

so im wondering whats the best use for gems?
So far i havent spent any...do you guys buy the chest in the shop? if so which on do you recommend?
What about spending gems or in the shop on a single card(if you scroll to the far right) there have offers for single cards that are changing every few hours? Is it worth unlocking cards this way?

Just wondering what you guys spent your gems on.

[Fuse]

I spend mine on the legendary chest, just wait till you get 1500 probably the best option