You need to understand how you can exercise trademark rights for them to be useful.  Many laws are aimed at preventing commercial exploitation of the trademark, so, for example, stopping me from making a tech company called Appel.  It won't stop me registering a username such as Apple somewhere.
It may be useful if you're producing something, eg "slushba's videos", stopping other people from making "slushba's videos" (though I doubt you'd go to the effort to sue in that case anyway).

Also, you need to renew trademarks every few years, or they expire.

Finally, a trademark is not actually necessary in any case.  Everything you could sue using a trademark, you could do the same without one (eg misrepresentation laws).  A trademark merely makes it easier for one to sue (as well as warning others not to use the mark).