I am booking most of my hotel stays directly with the two chains I am using. However, sometimes, when none of the two chains has a hotel where I need to be, I am using one of the three services (I check all three of them and I book the best offer - points vs price). Sometimes the offers are very similar, but many times they are not. And - if anything - I found the quickest in posting the miles post stay to be Kaligo (just 1-3 days after check-out), the second one Rocketmiles (10-14 days) and Pointshound is the slowest (up to 6 weeks).
Bottom line (for me): there may not be a lot of miles to be earned this way, but it is better than nothing (when using a non-chain hotel or a hotel in a chain where I do not hold any status), so I am glad such options exist.