I mine grin. My reason is simple I got a few low power low priced units around 20 months ago So I simple mine them and hodl the grin.
Power cost is under 1 dollar a day to mine them.
I have more than 12,000 grin which was over 1,000 bucks but has dropped to around 700 usd.
The dropped occurred when monero got dropped by binance.
I have some fear about mining on a big scale because if I had 1,000,000 grind and it went to a dollar I think it could be very hard to cash it out.