TaggedLogger - Log wrapper
I do not consider your class useless, I have actually done a similar thing myself. Very similar actually. Perhaps even exactly the same, pretty much.

Overall, your code is very well-written. You use final and private where you can, which I like.



A few comments:

private static final TaggedLogger LOGGER = TaggedLogger.forClass(MainActivity.class);


Even though it is correct that constants are written in ALL_CAPS. One exception for this is loggers. If you write LOGGER.info and stuff often, that LOGGER will pick on your eyes after a while. I would recommend using the name logger (lowercase) instead.



public static final TaggedLogger GLOBAL = new TaggedLogger("Global");


I am not sure if you really need this one. Especially not inside that class.

It is good that you have not made your class a singleton at least, but I'm not sure if this public static 'global' is really necessary.



I can recommend using log4j for Android for logging. Log4j is a very nice and popular logging framework for Java, and it is possible to get it working on Android.