It is claimed that Satoshi Nakamoto owns around 1 million bitcoins and he mined them when mining bitcoins was easy ("premine").
Well, if you want to call running masternode a ponzi, be my guest but in my opinion it is one way of mining coins. The coins need to be mined in one way or another in crypto.
You can buy many things with Dash as far as I know. I do not know how much it is used for buying goods/services, and that's up to the community what they within themselves want to buy/sell for Dash. Many want to speculate with the price increase and therefore are not too hesitant to use it but chose rather hold it for longer.