I would expect, or hope, that if any DT member would take that deal they would not be swayed by the amount received in order to give an honest review. If there ever comes any point where they (the ones asking for the review) starts talking about receiving trust that would be the big no-no. But just for a review, why not? As long as it is objective I don't see any big issues with it.
IOW
quid pro quo!
Paid reviews and paid advertisement are not new or inherently bad. As you say it's not a problem if it's objective (ie no quid pro quo). It's obviously really hard to figure out the quid pro quo part so everyone should probably assume (until proven otherwise) that all reviews and the like are paid reviews. Once a person has proven themselves to provide honest reviews folks can better trust the independence of reviewers by reputation!
This specific case is a bit of a joke just based on .02 ETH and I would be quite surprised if he got any live DT'ers, there are just way to many red flags for any sane DT member to seriously consider hooking up to this train wreck in the making!