Well, it might seem a lot at first, but it's actually not that much we get free on DMM, steam is better:
DMM:
.) 200 V-Stones after maintenance, a 100 extra if it's prolonged
.) when game hits nr.1 on DMM, we get 1.000 V-Stones
.) from monthly live-stream we get goods from the "live-gacha" like tickets, fruit, ticket frags, one complete SSR ticket each time, crystals etc.
.) Birthday event on DMM only paid users get to play the Birthday event games. At the beginning of this trend you were able to farm 8K V-Stones from the event, now only 5K - but you get a SR accessory and the ring and if you beat the last game with S-Ranking, you also get the Decobromide (only possible if you managed to get the featured paid Birthday SSR though)
steam:
.) 200 V-Stones after maintenance, a 100 extra if it's prolonged
.) Birthday events are playable for everyone AND if the cummulated userbase reaches certain perks, we get awesome goodies: red tickets, Venus tickets, V-Stones, full SSR-ticket AND most important of all: a free SSR Crystal each time.