$8m / year for a 16ppg 4ast guy is a steal for any team if they need a guy like him or not. baring in mind Mann came over the bench averaging these numbers ,meaning his number will translate to Cavs team.
cleveland shed $12m/year and are able to make moves as they will no longer have to face 2nd apron repercussions because of a trade like this. whilst building on their current minimal draft capital which could also allow strong trades for high level players later this season or in those to follow .
But anyways For a team that will be looking to shed salary, you either strike for a really efficient trade like this (stats & contract wise) or you look for a trade where you will have to receive multiple third-rotation-level players who will be useless - similar to what the Celtics got in return in that Porzingus trade. There are not many cheap highlevel players on market rn, and those that are (like your Keon Ellis's) are will be overvalued in a trade.