Hi @merej99, good to see you back in circulation!
What do I think?
Well, a couple of days ago, I wrote a piece questioning to what degree cryptocurrencies are actually "currencies" (as opposed to something more like common stock)... and what we need to do to create "economic systems" to lend cryptos a greater level of utility. Which, I believe is ONE challenge we need to overcome. The mainstream don't see cryptos as "useful" since you can't just pop down to 7-Eleven and buy a sixpack with Bitcoin.
The other challenge, I think, is volatility... and especially the ongoing trend that cryptos can increase massively in value. Why would you SPEND your Bitcoin on a lawnmower if you could just hang onto it and have enough for THREE lawnmowers? It creates a strange lack of... product-liquidity... because actually using cryptos isn't always the most attractive option. If the price/value were more stable-- like SBD-- I think mainstreaming would become easier...