Personally I think it's not so much about separation of concerns/technologies per se, it's that this debate boils down to a different debate under the hood: the one about folder-by-type vs folder-by-feature[0].

The gist is that folder-by-feature is generally preferrable because it requires less context switching (in the literal sense of jumping between multiple different far away folders and scanning each for the thing you're looking for)

Single file components force you to organize code in a folder-by-feature structure, to a large extent. You can use folder-by-feature structure alongside with separation of technologies, it's just not that common to see it because the tooling to support it is not quite as optimized.

[0] https://softwareengineering.stackexchange.com/questions/3385...