I think this pretty much puts a nail in the coffin for both the RX Vega 56 and 64 seeing as the RX Vega 56 alone consumes 91 watt more on load than the 1070 in which when calculating the power consumption difference in 1 year alone let alone 3, could get you a lot of money that can be used for other things such as a more powerful graphics card instead.
I am bad at explaining but his video does it justice taking into account, stock, overclock, idle, load and daily use (4 hour load, and the rest, idle)