Comment by nine_k

> the average domestic connection being gigabit

This strongly depends on where your domicile is, even in Europe and the US. And lot of the users live outside these areas.

> JPEG was fine in the days we had much slower connections

Except that waiting for a large picture to load was very much thing, and in many cases still is.

> What are the benefit for the final user?

A number of users are still on metered mobile plans, and have little storage on their phones. With the current situation in electronics production, new phones are not going to offer more space, cheaper; to the contrary.

Also, publishing larger / better quality images becomes easier and cheaper.