Better way to spend energy refreshes?

I myself was a bit slow realizing how much a difference a high arena rank would make for your overall progression — but as soon as I started focusing all on my arena team and future arena toons, I worked myself into top—35 at first, then top 20, then higher — and those extra crystals really make a huge difference. I would advice to do the same. Prioritize your arena squad and use whatever leftovers on your raid squads etc.