TL;DR (From Android Authority)
• Mozilla responded to a review mentioning the lack of tablet UI optimization for Firefox on Android.
• Mozilla confirmed that its team is not working on optimizing the tablet experience at the moment.
• Mozilla did, however, say that it hopes to revisit tablet optimization when time and resources permit.
Regardless, this is important.
This means that, for tablet users, the option is between Chromium on Android or WebKit on iOS, unless they’re using a Windows or Linux tablet.