Monero is certainly an interesting coin. Their extremely high focus on privacy makes it unique compared to Bitcoin and other cryptocurrencies.

I think privacy brings own benefits but it also has risks. Like Michael Taylor in the other answer mentioned, wealthy people could use Monero to avoid taxes. Also, drug dealers and other people who make illegal business can take advantage of privacy and untraceability.

Still, I think that Monero has great potential and most likely it will be in this realm for long.