The gold bonus from the pickaxe skill is fully passive and its effects are team-wide. That is, anyone who picks up a coin with a level 7 pickaxe in the team, will get spoils worth 5 gold more (per pickaxe). And it stacks. The idea of that talent is to get it on level 8, so your team feels the full effects of it throughout the whole game. The later you pick the talent, the more useless it will be, but in the early game it is very powerful (obviously the pickaxe has to sacrifice getting that over any of his other talents). If you have 10 pickaxes in your team, coins will be worth 50+ gold. If they take the talent, then 100+ gold. It is actually pretty powerful, especially if you have 2/3 pickaxes on your team (which is a viable strategy). I'm slightly inclined to nerf it because it is powerful if stacked.
It has been reworked before

, i may just change it into +gold per round (for every player or maybe just himself). I'm not sure yet...
I have had mixed feelings about gold drops for a while. I only put it in because in the old OG, getting the last hit on creeps was really the only way to get a good amount of gold. Last hitting is a very archaic mechanic, and the next best thing i thought as a bonus would be coins. Obviously coins drop on the front line, so your ranged people are missing out on drops and gold. My current future rework would be something like this: every round, 3 coins
will drop per player, and the drop chance is much higher (say 10%), so drops are random, but limited, and coins give less gold, but give gold to
all players, and despawn after 10 seconds if not picked up (so clicking them is still important).
Probably is a tooltip error, there's so many to track

, if i change numbers in the triggers, i might forget to update any affected tooltips! That talent was buffed in the past so it makes sense i forgot to update it.