I guess sell it. People think it's valuable. Cryptocurrencies are priced not valued. You can't just go Dogecoin is valued at X. Dogecoin is priced based on supply and demand which is saying it's worth $91MM.
All Dogecoins in circulation are not worth $91m. For that to be the case, there’d have to be people willing to buy all 111 million Dogecoins for $0.000796 each, which is not the case at all. People are only willing to pay this price for a tiny fraction of all Dogecoins in existence; as we go beyond that, the bid price starts approaching zero.
The opposite is also true, and not just in assets like stocks but cryptos as well.
The price of any asset increases substantially if you try to buy a significant stake.
It's not any fundamentally different than Bitcoin, in fact it's probably better for money laundering than Bitcoin because nobody cares. Furthermore, the market cap was $400MM a few months ago, so does that mean we're still in a "bubble"?
As David Gerard notes, market cap of cryptocurrencies is a false and misleading metric. Look to total circulation volume/time, and realise it is exceedingly thin.
Some people say that moving Value from one exchange to another is cheaper when using DOGE than it would be using Bitcoin.
Whatever you want. Crypto currencies are the fiat currency end game. Get enough foreign currency cross pollinated via bitcoin (and assuming enough political clout) and the world will suddenly change.