Writing this on FF for iOS, the biggest reason I want to use the Firefox engine is for Firefox extensions. WebKit doesn't support extensions except the App Store ones in Safari, I want to use traditional extensions from AMO. Just let me use uBlock on my phone!
I do agree, the Firefox iOS UI is clunky, but I find it useful for stuff where I want to sync passwords or tabs. I use Safari for browsing the web casually because it's nicer, and the feature of swiping between tabs is so convenient.
Just to correct the common misconception. It is browser vendors that need to build web extension API support on top of WebKit. Orion browser [1] did this both for macOS and iOS . The support is still in beta and improving with each new release. iOS support remains limited to what is possible to achieve with a JS wrapper. Nothing prevents Firefox from doing the same and offer at least partial web extension support on iOS.
WebKit does support the same extension API as Firefox - it’s an open standard. How you install them, bundled in a native app from the App Store, is the annoying clunky part.
WebKit does not support blocking Web Request, which is what uBlock Origin uses (See compatibility matrix at the bottom of https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/Web...)
In fact, it is all about blocking Web Request, not say, Manifest V2 vs Manifest V3 (Firefox supports MV3 but adds blocking Web Request support.)
I do agree, the Firefox iOS UI is clunky, but I find it useful for stuff where I want to sync passwords or tabs. I use Safari for browsing the web casually because it's nicer, and the feature of swiping between tabs is so convenient.