Why are templatetags stored in directories?
Django expects you to arrange your apps in certain ways. Requiring a templatetags directory in the app is not the exception. Some other requirements are:

ModelAdmin in admin.py (for autodiscovery)
Models in models.py
Management commands in management/commands directory
Fixtures in the fixtures directory

Unlike templates, where there are hooks to specify how your templates are loaded, there is no easy way to store your templatetags modules in a different location.
I'm now working with template tags and one thing I haven't understood is why do template-tags have to be stored inside a templatetags directory in the app. Is there an underlying reason for this? Is it possible to store them in a templatetags.py file somehow so that I can reduce the extra bloat around having extra directories?