If you're not relying on your translators to produce production assets, then you will be converting them from a format they are comfortable with (which tends towards Excel, if not a web app of some flavor) into whatever you're using. Unless you have a particularly rough memory budget, you will almost certainly be saving yourself time and effort by cutting out a step.
If you use a web app of some flavor (AirTable, Google Sheets), conversion shouldn't be a problem though, should it? Or are there good reasons to avoid these options that I'm not thinking of?
It's another step you have to automate in your build pipeline, have to tag and manage outside of source control (making your builds now "code at rev X + assets of difficult-to-isolate revision Y", which makes repeatability a little harder), and so on and so forth.
You can do it, and it has its advantages. But you're also buying complexity.
We have used json, xml, ini-style files, or csvs, which, as i8n goes, has been pretty easy