I'm not using any other crypyto currencies instead of BTC and many other people also could think like this so BTC has no competition in the market right now
But not till the end until the new advanced technology which is more attractive than block chain there is no competition to bitcoin
In these past years of having the digital world currencies or also called cryptocurrencies are gradually spread across the country and other developer creates a new crypto to lead on the top so I think there's a competition between the cryptocurrencies including Bitcoin.