Now when these first came out I instantly dismissed them as being a business cash generating exercise to exploit gambling and that there would be no value there, but I think I was wrong.
On first glance, you have three players that sit down and put in, say, $1 each and then play for a $2 prize pool most of the time. Which just seems like an easy way to lose money quickly. However the prize structure is actually equitable, 8% rake is taxed from the buy-in but thereafter all prize money is distributed fairly, as the following table illustrates. Sum up the third column and you get the contributions of the players for a single Spin & Go (less rake of course).
I've used prizes from the $1 Spin & Go games here but it looks like they just scale with buy-in, so this should be equally true for other stakes.
Prob x Prize
It's also tempting to think "well surely in order to get full ROI from these games we need to cash big sometimes, and 1,000,000 to 1 doesn't look like great odds to me". Well this is partly true, and there may well be better uses for one's investment if we can't put in the hours or play the number of tables required to pick up the larger prizes.
However these games may have more recreational players than others; those gambling for a big payday. Referring back to the table above, 99% of the time we'll be playing for $2, $4 or $6 at these stakes. If we can cash 40% of the time then we can make 6% ROI without even taking the larger prizes into account!
It is certain that good regulars will have looked at the maths and will know all of this, so it's likely that there are Spin & Go specialists playing these games.
I'm not sure what win %s are realistic in 3-handed Hypers though I saw a HUSNG professional do very well in Heads-Up Hypers a few years back. I suspect 40% is manageable at the lower buy-in Spin & Gos but this would require quality short handed and heads-up play.
Anyway, I was foolish to dismiss these out of hand, and as I'm only a recreational player these days, I might play a few for fun!
This link explains it all much better than I did!