Scalability issues:

Lightning Network (and possible other future L2 solutions)



Price volatility:

Not a disadvantage, simply part of the process of price discovery of an asset in its adoption phase.



Environmental concerns:

These concerns are from people who don't understand how mining works. The end result of mining is strengthening society's electrical production and specifically helping renewable energy by operating with excess energy at power plants or stranded renewables. Sure some energy use will continue to come from fossil fuels for as long as society uses fossil fuels, but that's no different than literally anything else in the world that uses electricity.