If 250 MB of ram is an issue then you probably aren't doing much modern web browsing. I have what I'd think are basic pages that are using 200MB of ram. Same if you don't have the 300mb of free space, god have mercy on your soul if you've got less than a gig free.

The amount of ram this feature takes up is negligible compared the the bloat of modern webpages. Plus I'm sure there's an about:config setting to disable it if you want to go crazy.

While I agree, I think there's a pretty large community (like myself) who will use this regularly.

Though I'm unsure of the statistics on how many would use it. If it's under 50% for sure should have been an extension.

Because it's just using a pre existing translation package. It's not a big and complicated system, the big and complicated part was done by someone else