[JohnFen]

It's isn't the default because the countermeasures cause a lot of side-effects. If it were on by default, new users would probably think the browser is broken or buggy.

Here's what the settings do and what sort of side-effects you might experience:

https://support.mozilla.org/en-US/kb/resist-fingerprinting

[Yeul]

Yeah I have it on but I use a second browser for banking and government business.