1. Transaction rate. Check out BTC its always in 20K-30K transactions behind
2. Decentralization. We dont want china to tell us what to do even theoreticaly
We also have business oportunities. From the top of the list:
1. Smart contracts is radically new and awesome idea. Just check out what BitMEX did with XBTUSD contracts, totally awesome.
2. Wide adaptation of crypto on regular markets
So
I invest in smart contracts. ETH, NEO, WAVES, Stratis
And in faster transactions. BitShares, 0x, LTC
I like WAVES a lot by the way, not the best solution but very solid and well built.
I agree with the two main challenges but to add a third is security/privacy.