I don't use a display manager because you can enable X forwarding, which, IMHO, should be manged by ssh.
Windows mangers as GNOME and KDE now come with PolicyKit, also fuc*ing with security. Not speaking of sudo. Not speaking of auto-mapping.
Keeping a DM out of the way is one security setup less.
Now, startx being a shell script, there is no reason why it can't be called from/included in the login.
Most of us type startx (or startxfce4 which is a choice between 2 WMs really
)
I guess we all like to see what happens on the console when we login.
I also like to call X apps from a console, standard output can be so instructive.
Bad habits maybe.
Now, if it is just for a desktop and browsing, projects as PC-BSD could be better choices (even some minimalist Linux mini-CDs: no pun intended, no shame, just use the right tool for the right job).
If the goal is learning, spend some time with OpenBSD.
Oh! Yeah! I *always* have a xorg.conf file, as autoconfigure cannot guess if my monitors should be configured as dual, clone or xinerama.