Should related assets be created in the same or separate Blend files?

I’m creating a myriad of assets (for things like https://en.wikipedia.org/w/index.php?title=Czech_hedgehog&oldid=1221140115#/media/File:Rozsocháč.jpg and https://en.wikipedia.org/w/index.php?title=Bunker&oldid=1207940710#/media/File:Maginot_line_1.jpg) all of which shall be used to create renders, but also later in games as (probably) interactible objects.

Considering the multiple purposes that these might serve, are there any technical benefits for me to include multiple assets in each blend, or should I have them stored in separate .blends?

In a situation where you have to do

having the beam for the hedgehog separate from the rest of the hedgehog was incredibly useful, because rotating the beam completely screwed-up the horizontal mirroring:

and https://blender.stackexchange.com/revisions/96348/2#:~:text=Apply%20the%20rotation%20to%20your%20object%20Ctrl+A%20>%20Rotation doesn’t appear to do anything.

However, it appears to have as many disadvantages:

These prevent it being of use.