You can see the reason if you check the coinmarketcap and doge coin still on strong position that's why you can see many people still believing on them, and also why would he focus only with Bitcoin while he can both avail them and sell whenever they are price changes happen in 24 hours or maybe even in next following days. Remember it's so better to have an strong alternative so whenever if there's a lost on the other investment you can recover it ok the other half.