since we can make use of bitcoin instead.
Who is "we" ?
I'm asking because personally I prefer paying with litecoin instead of bitcoin. One of the reasons is because prices make more sense in LTC than in BTC where you end up using zeros after the decimal. Of course you can say "satoshi" but usually you just see amounts in BTC.
When I know that LTC is, for example, 50 EUR and something costs 2 LTC, in an instant I have a sense of the price in my everyday currency, the euro. When I know that BTC is about 3500 EUR and something costs 0,03 BTC I cannot adjust that quickly. But then again, that's how it works with me.
I'm sure someone else prefers to pay in DASH for his own reasons.
So, there's no real "we". There are lots of currencies, and we all pick the ones we like to use.