That is the core problem with product management: Presumably every feature is useful to someone, somewhere, but you don't have infinite engineering resources to ship and maintain them all.

No one is suggesting the feature isn't ever useful. The issue is that they've reached a point where they have to choose what stays and what goes, and the least frequently used features are obviously at the top of the list for what to cut.

You can't make everyone happy in these scenarios, just as you can't deliver everything.

To make a concrete argument here: If Mozilla has the sweng resources to devote to their frequent frontend redesigns, they can keep the encoding menu working. And the encoding menu has a significant, difficult-to-replace function to serve for people from non-english-speaking nations who want to consume content in their native language. For reference, I worked on Firefox.

Removing something like the encoding menu is a choice, not a necessity.

Right, but I'm challenging the notion that use means usefulness. I don't think that can be assumed to correlate without further justification, especially given the ease of producing counterexamples and scenarios where this is not true.

Some features are used a lot because some other features are inefficient. Sometimes a feature is very useful in some rare situations (compare with seatbelts).