My current understanding of the services has them not at the price point that people would like for this. I think many people would like to get rid of their stack of papers, and would spend a day of their time on it, but would not pay a scanning service. I don't expect to just throw in a stack of papers of course, but what I do wonder about is taking a "stack" that I have done a bit of work to order and straighten. Some will scan no problem. Others were once folded (like bills etc.) and I would expect are more of a challenge.

If jams and bad feeds are going to be common, a fast scanner makes more sense because you would expect to sit there, feeding and unjamming, and if it's 60 ppm, you will spend little time just starting and most time in feeding and unjamming. Which is actually good.

I would expect decent clean feeding for things like well stacked documents pulled from binders, magazines and books with spine chopped off etc. (Google of course can't usually chop spines which is part of what makes the digital camera approach they and Internet Archive use make the most sense.) I would expect more trouble with the contents of my old filing cabinets. Business cards, if supported, should do well.

(For business cards, and other alternative would be for somebody to code a sheetfed scanner which is the width of a page to let you feed in business cards in parallel, zipping from left to right as you feed them in. That would let you do your cards much more quickly than any business-card only scanner unless it has a perfect autofeeder.