Augment the FAQ

docs/contents/faq.md

@@ -12,3 +12,18 @@ and then set the `DMENV_NO_VENV_STDLIB` environment variable to a non-empty valu
 * Because it's my second favorite language
 * Because distribution is really easy
 * Because by *not* using Python at all `dmenv` is less likely to break if something on your system changes.
+
+#### Why should I use dmenv and not existing tools like pipenv, tox, poetry, flint, ...?
+
+`dmenv` works really well if:
+
+* You already know how `pip` and `python3 -m venv` work
+* You don't really mind that `pip` does **not** solve dependencies
+* You want to be sure your code can be published to pypi.org or any pip
+  mirror if you need to
+* You want your code to work with several versions on Python
+
+Compared to other tools, it may be much faster, but at the cost of having
+less features, or be harder to use.
+
+Please bear that in mind when considering using `dmenv` for your own project.