Why not a pure black and white (1bit) option?

I've asked this off every other Android scanner app developer and have yet got a reply. When I open up a 'greyscale' pdf created in a scanner app I  Acrobat pro I've noticed that they are always faux greyscale. That is, the images are saved in 3 channel, 24 bit RGB, not 8 grey.

I just installed this app but haven't tested it to see if it does the same, but I somehow suspect so. Given the data savings and the limited storage of mobile devices, I would have thought every effort would be made to give the users a chance to make smaller files.

And going even further, why not a pure 1bit black and white option? Given the high resolution of many device cameras now, 1 bit would be more than fine for good readability and faster /easier sharing/printing and storage. I've tested 1bit converted versions of pdfs made on Android apps and they function fine for viewing (with my Samsung Note 4, it's a 400 dpi embedded image). What's more, the pure bw versions are anywhere from 1/4 to 1/10 the file size of the ones I source them from.

I would think that if anyone could understand and implement this option well it would be Adobe. When people understand the advantages, it could be a real selling point.

Granted, it would work best for plain, pure, 1 colour, solid originals. But that fits for what I would guess are a majority of scan targets: cash reg receipts, invoices, most business cards.

I hope Adobe will consider taking the lead on this.