The lightning network has a lot of promise, but there are remaining hurdles. This article discusses some of them.
As I like to say, a good idea and good execution is not enough - you need adoption. The lightning network is growing, but it needs many more people, more education, and much better user interfaces. It also needs lightning to cash/bank account gateways.
Adoption is difficult - the SegWit upgrade is still at just 50% of transactions, even though its benefits are clear.
On the execution side, routing needs to be improved. Security needs to be improved (drastically, since you must have bitcoin online to use the lightning network). Perhaps hardware wallets will implement lightning.
The point about price volatility is valid. If someone commits a small amount of capital to a channel, a big increase in price could result in too big a target (incentivizing hackers). A drop in price could reduce the usefulness of the channel. This will need to be addressed.