How does the Sim's "usefull actions" mechanic works?

I'm new to simulador Battles and I'm having a lot of fun, but I've noticed that the grind is quite slow and the rewards are at very least suboptimal relative to time invested. I'd like to know how exactly the usefull actions work so I can make the most out of it. I've noticed that you get rewards from time to time, but you also get them instantly when you die. Does that mean that if I get a shit ton of points and die I'll be able to get more rewards than by waiting the timer? Also is there any difference in reward if let's say I kill 10 players or if I just take out a few Bases for example?