Well I thought about that at first. BTC will be used but most likely for high end purchases such as international trade settlement, car, home, student loans etc. Most likely LTC, BCH, Dash or others will be used for daily purchases such as coffee, shoes, etc. Bitcoin is also much more than a crypto currency. Check out this article I wrote a week ago and let me know what you think. https://steemit.com/bitcoin/@jetblake/important-fact-about-bitcoin-and-why-it-could-be-usd1-000-000-00-within-5-years