No. You have the choice to use either named branches or bookmarks, and which one you choose is a matter of your workflow. Note that even a Git-like workflow does not necessarily require the use of bookmarks.
Mercurial is still designed under the assumption that people will use named branches and the Git-like aspects of bookmarks exist to ease transition from Git: http://www.selenic.com/pipermail/mercurial/2014-January/0464...
Personally, I use Fossil-like private branches [1] in order to facilitate local work that I may still want to reorganize before pushing it to a shared server; I use bookmarks solely for local tags.
[1] Emulated by putting a named branch in the secret phase. I actually have a simple extension to automatically make all branches that start with a dot (e.g, ".tempstuff") secret.
These days, the standard practice is probably to use bookmarks, which are more or less like Git branches.