What about powerdraw?
1 AMD 5700XT van do 50MH/s at around 150W. However that card is much cheaper than a SQRL card and can be sold to gamers when you dont want/use it anymore.
i don' t know about amd 5700 xt but with my mining rig of 5 rx 480 8gb mining edition and 1 rx 580 8gb i do 27 mhs plus 29 mhs for rx 580 with a total power consuption of 950 w effective. (platinum psu)
With forrest kitten we have 130 w and 50 mhs (for now) effective cause there isn' t ram, cpu, etc. i think they can upgrade to 70-80 mhs, but i don' t know