This complete speculation and mostly goes against the traditional narrative (i.e. Putin's legacy is now staked on the Ukraine invasion) but it would have accomplished the following, basically giving them more options and room to maneuver (both on the battlefield and in the political sphere):
a) Allow Russia to disengage/extricate itself from Ukraine with a plausible/save face reason ("internal security reasons") b) Let them re-position Wagner forces to Belarus or along other boarders c) Lull Ukraine/the world into a false sense of security d) Purge/re-organize their military high command
I wonder if this plane crash is part of it?