I first need to Date Myself, by saying that my first Linux Distribution was Yggdrasil Plug and Play Linux, purchased as a CD in December, 1992.
My first impression of Linux, was as a Multi-User Operating System, with different User Names. So I organized my Working Environment that way, even after getting Graphical Environments to work. And I made Usernames, based on Function such as, for example, devel (for Kernel Development) and hercules (for IBM Mainframe Emulation, such as MVS 3.8J. Google "Plug and Play MVS" for more information).
What made Linux special, in my opinion, was this Built-In Multi-User Multitasking Functionality.
And it worked fine, all the way from the beginning, by having the original Init Process Spawning 6 Login Processes (using /bin/login), that "listen" on /dev/tty1 through /dev/tty7. (And, if a Graphical Environment is running, it appears to be on /dev/tty7).
If I was, simply operating in Text Mode, I would switch Virtual Terminals with Alt-F1 through Alt-F6. If I start something on one of these Virtual Terminals (i.e. Compiling the Linux Kernel), I would trust that it would continue to run, while I do something else on another Virtual Terminal (i.e. using emacs or nano to edit a text file).
One "Special Function", which pointed out the "Fly in the Ointment" to my above description, is Background Music. I LOVE Classical Music, so I would have a Symphony Movement (mp3 file) playing in the Background, through the play command (sox package) on one of these Virtual Text Terminals.
The reason I am bringing this up now, is that I tried this on Stretch, with no Graphical Environment, only to have the Music (playing, through the play command /dev/tty3) *STOP* *COLD* when I used alt-F4 to switch perspective (say, to /dev/tty4!)
Looks like SystemD may *NOT* be spawning the 6 Text Login Screens, like the SysV Init Package did?
Thank you and best regards,