Ak-shually… you’re completely right!

But you left out an important option for OP: they can just turn on auto-login and bypass the login screen entirely. If they want any security, they’ll need a display manager, but maybe they don’t care. Also, while this doesn’t apply to them, I discovered accidentally that after I log in to herbstluftwm, it goes directly to screen lock. I don’t know what I did to make that happen, but I’ve realized I can just disable the display manager, have auto-login, and still get security. Probably not as much, and if I ever get around to encrypting home that won’t work anymore, but I’ve been considering doing it because typing my password in twice is a drag.