I agree this is probably the easiest and most efficient way to make the website suitable for mobile devices.

But is Special:Translate itself usable in Timeless on a phone? Did we get some testing on that? Do we have some statistics on how many active translators have chosen Timeless as their skin and can we maybe ask for their opinion?

Before such a switch, we would need to determine how we're going to check any negative side effect, how many translators are getting lost in the new skin for whatever reason, etc. It's not always easy to communicate with our very diverse community of translators. At a minimum, keep track of how the activity statistics evolve? But I'm not sure that's a reliable indicator of user (non) frustration.

In T248064#6071335, @Nemo_bis wrote:

But is Special:Translate itself usable in Timeless on a phone? Did we get some testing on that? Do we have some statistics on how many active translators have chosen Timeless as their skin and can we maybe ask for their opinion?

It works better, because sidebar gets automatically collapsed. On the smallest screen sizes, the translation editor is not usable.

https://translatewiki.net/wiki/Special:UserOptionStats/skin

Before such a switch, we would need to determine how we're going to check any negative side effect, how many translators are getting lost in the new skin for whatever reason, etc. It's not always easy to communicate with our very diverse community of translators. At a minimum, keep track of how the activity statistics evolve? But I'm not sure that's a reliable indicator of user (non) frustration.

I'm gathering feedback before (and after if it's positive) the change is made.

Cross-linking: https://translatewiki.net/wiki/Thread:Support/Proposal_to_change_default_skin_to_Timeless