@joker
1. limited gear which needs usage points, having that bought doesn't imply you can use all of it at the same time, you may have just more of it as you bought items which use less of those usage points.
2. Everyone has the same pool of usage points, they are fixated, investing would be done by buying restricted gear which use up those usage points. like 70/100. Here 30 are still left you could either buy another high tear gear which uses f.e. 30 or 3 low tear which use up 10 each.
All these items which need usage points also get a counter depending on how much usage points they used up. The more the less time you can use them. That would have the effect that the developer could have an actual way to calculate ahead how much of different types of gear is used and may therefor concider this as an additional balancing tool to reduce certain types of gear on the battlefield dependent on how often not on if at all it is been used.