To me the Alpa system is meant to be in a little bag with wide lens (I use schneider 47mm and 24mmXL) with a digital back or a 6X9 film back : great portabiliy with maximum quality.
That is why I have never been attracted by the FPS, it is not for my use because of the size, the form factor, and the weight and the price. When I want to put legacy lenses, I have a Sony A7 with adapters for that.
But my joy is to walk about with my little bag, and a one lens combo with the TC or SWA.
Being curious let me understand the attraction for the FPS, but it is not for me. Enjoy and shoot !

Stéphane.