Plex is more and more popular. I think this time to make the home page, some help section and all the email (server sahreing, friends, etc...) sent by Plex translatable in other language.
For example I'm starting to share my content to family, but the first contact is not easy if user is not fluent in English. I've to make distant support and the first impression is not so good.
I'm sure if some people from this community actively translated the text and supplied it to Plex they would be quite happy to add some other languages than English, its all down to having people that can translate at a high quality, than google for example.
I agree with you but before starting translations, it could be interesting to have the dev team point of view. Perhaps there are other priorities or some technical constraint which could make difficult to deploy the translations.
For example, I've already propose a Chanel Store translation in the past and it never happen for the moment.