Let's suppose we get 200 active players in one day(I believe we have way more than this), each of them would receive 5k, this would inject 500k in the economy every day. This is way too bad for the economy.

I kind of like the idea but not the way you are proposing. Maybe something like, 100 + X% where X is the amount of consecutive days you are playing with a limit of 100 and you only get it once you win Y ranked matches. This way not only activity but also ranked matches would be encouraged.