Neither of those things are completely true. While bitcoin is accepted at some merchants, volume is pretty low. Several have removed it. People don't really use it to buy things, precisely because the network is stagnating and congested. The vast majority of Bitcoin's value derives from speculation, just like Ethereum.

Also, Monero is also on equal terms with Bitcoin when it comes to dark net markets. Another crypto with an actual valuable distinguishing feature (true anonymity) has more of a use case than Bitcoin here.