Splitting translations for a locale into multiple files

[cernymatej]

Hi, I'd like to discuss whether it is better to keep all translations in a single file or to split them into multiple files.
I was hoping that splitting them would allow the files to load lazily, only when a key from a certain file was used. However, I found that this is not the case.

locales/
    en-US.json5

VS

locales/
  en-US/
    cart.json5
    labels.json5
    user.json5

// file example:
{
    user: {
        my_account: 'My account',
        dashboard: 'Dashboard',
    },
}

I imagine that since the individual files are not loaded lazily, it is more performant / efficient to have a single large file that is downloaded in one request, isn't it?