I've spent too much time drilling into this esoteric issue without getting to the bottom of it. Having initially used and then rejected the use of "Takes" in putting a project together, I'm now inclined to return to them to avoid rendering individual clips prior to rendering a final project file (which is what I have been doing) - but have come up against this conundrum. So far as I can see a "Take" (largely deprecated by the experts on this forum, I believe) is the same as a "Scene", the only difference I can make out being that a "Take" is a scene that has been assigned a unique TK2 file and shows up as a thumbnail in the Media Pool under "Takes". It is automatically identified by its parent file and numbered according to its sequence in that file, and being in the Media Pool it's easy to select and slot into place in a project without the need to open the parent file on the timeline for that purpose.
"Takes" don't work too well in MEP 2020 (that I do know - I tried that update and reverted to MEP 2019 as a result) nor in MEP 2021, reportedly, but are fine in MEP 2019 - once I sorted out the correct way to use them...
There must be some advantage to using "Scenes" instead of "Takes", because no-one appears to be using the latter - but why not, given the advantage outlined above? Alternatively, why are "Scenes" the preferred method for creating clips? I would really like to know before proceeding any further down the wrong road.