itcoin - currently used as store of value and pretender for gold 2.0. Bitcoin can be considered as the cryptocurrency king, simply because of its first mover advantage, great network effects and security of its blockchain. The computing power required to secure the network is 1000 times more powerful than the worlds top 500 supercomputers combined. If you calculate the costs of those 500 supercomputers, Bitcoin compounded computing power is much cheaper.
Bitcoin has limitation to processing around 5(theoretically 7) transactions per second, which some consider is hurdle to be accepted as global payment method. Bitcoin can be consider the strongest p2p financial network in the world.
There is a lot of difference between Ethereum and bitcoin. Bitcoin is the pioneer crypto in the world and the market cap is far better than Ethereum. Ethereum is no doubt good coin for investment but I think there is no comparison between these two currencies. People still like bitcoin the most because they think that only bitcoin can give then big profits.