There's no benefit to dating sites to matching people who are truely compatible (assuming this concept even exists, and assuming they had some way to assess it)

There's no benefit to dating sites to matching people who are truely compatible (assuming this concept even exists, and assuming they had some way to assess it). All that would mean is they have lost two customers. Much better, and easier, to match two people based on the superficial factors that we're wired as humans to look for - good looks (as good or better as ourselves), etc.