Firefox Focus (FF) is a browser developed by Mozilla for iOs and Android platforms with privacy in mind. The biggest selling points is that a) it automatically blocks trackers, and b) cookies and browsing history are easily deleted. Blocking trackers has the desirable side effects of faster loading times and that some ads get killed in the process. It's like always browsing in private mode, which has its uses in this age. I have been using it for a while but stopped due to some shortcomings that didn't have easy solution. Then I ended up using a different solution that brings pretty much the same functionality with better usability.
It's 2019 and the web is a mess
It's 2019, we have GDPR and other local laws, so websites on the European quadrant of the world feel the need to warn the user that there will be cookies, third party tracking, general bullshit on their side. Plus, these warnings are only shown the first time you visit their pages. In my desktop I deal with these annoyances in two ways:
I allow the cookie for that site to live in my computer. More on this later.
I use uBlock Origin to set up a rule that kills that element and forget about it.
However, with FF every time one access a page it's like the first time, and there are no exceptions, so the annoyance is never ending.
No ad blocking
As I said before, ad blocking is one of the anti-tracking byproducts. The downside is that it doesn't always work; I've even seen some pop-ups getting through from time to time. FF does not allow to install extensions, such as uBlock Origin mentioned above, so there is little one can do to fix this. There is a project to add an ad-blocker in future versions but that is not here yet, plus I guess it'll open a completely different set of problems.
Apart from this, there are other small details that make FF not very optimal to use sometimes:
Can't really open tabs: as the instructions indicate, a new tab is opened when a new link is opened. But there is no way of opening a tab for typing in the URL bar after, or at least I haven't been able to find it; essentially tabs need to be reused after they are opened.
All of the history is deleted at once: there is no way to close a given tab, so it's always either all or nothing.
Some sites really go to 11 with their anti ad-blocking protections. For instance, FF can't open links within Los Angeles Times, for example.
There are no bookmarks. One has the possibility of letting FF remember certain URLs so it autocompletes them when typing, but that's all.
If you use some site that needs you to log in, you'll need to do that every time.
A better solution: standard Firefox with extensions
After a while using it, I think that FF has a very clear use case: you open links from e-mail or text messages, read them, then delete the history and pretend nothing happened. This is not really how I use the browser on my phone, so I started looking for other options that don't go through Google1.
It turns out that the optimal combination is simply installing the regular Firefox browser plus two extensions (yes, Firefox mobile lets you install extensions!) that I also use on desktop: uBlock Origin and Cookie AutoDelete. The first one is a general-purpose blocker2, and the second one provides the very nice functionality that cookies die as soon as the containing tab is closed, unless that particular site is whitelisted; essentially, cookie-wise we are always running in private mode except for a bunch of sites, such as the ones we want to remain logged into.
So now we have the best of both worlds: we can remain logged in into a particular site, or allow a certain page to remember us so it doesn't show any cookie banner, or we can block that cookie banner entirely, and for the rest of the Internet we don't really care about (99 % of it), it's like we never existed after the first visit.