Funny story came to mind: You ever have a client accidentally hit F12, then tell your boss that your product was broken because there was a weird thing taking up half the screen?
Seriously: My guess would be download size, performance, maintenance. Especially with Moz aiming to target super cheap hardware with their OS.
It seems like it’d be beneficial to many web publishers if browser users couldn’t easily access underlying resources, and those companies could incentivize popular vendors to go in that direction (and every decent browser auto-updates, of course). Suddenly bypassing Flickr’s spaceball becomes too complicated for regular user.
On the other hand, no one would bother with that in a world where non-mobile computers are increasingly becoming developer-only machines, so this is probably just mild paranoia.
That's a really important aspect, are desktops going the route of developer only? (Non-web) Designers and other white collar probably don't need it, but they use machines that wouldn't notice the difference...
With FFOS, Android/Chrome, and MS there's a conscious effort to eliminate the difference in development between desktop, tablet and phone. With more people using computers, not as many people need or want desktop apps and those features on all of their desktop apps. If I suddenly need to edit an image, I don't need PS or even Gimp, I'm often fine with a web app.
And as for the new tool, since it also shares the Mozilla engine, it's as if you're using Firefox (+ some plugins) with regards to web behavior.