Advice on spending event badges

Hey all! I could really use some advice on which direction to go with my event badges.

My initial goal was to save up the 250 for this event's background, because I don't have one yet and figured the extra coinage wouldn't hurt. However, I've reached a point in my build where I'm now really tempted to skip the background and get gems and power stones - 105 badges for 300 diamonds would unlock my 4th lab slot, and 105 badges for 30 power stones would be my second ultimate (got GT as my first, so BHD would be huge).

I have enough to get both the gems and power stones now, and am 15 badges shy of the background.

Go with the background for extra coinage (farming tier 3 atm, have yet to attempt tier 4) or get the gems and power stones? Any help would be greatly appreciated!

Thanks y'all, and have a great day!