In MATE 1.24 a elogind compile option was introduced to mate-session-manager and mate-screensaver .
When installing packages
polkit-elogind, among others WiFi can be turned on/off with media keys and a suspend button becomes available in the shutdown dialog.
If elogind isn't installed, this commit has no impact on the behaviour.
Reference to compile option in MATE source  and how Gentoo is setting it up .
-  https://mate-desktop.org/blog/2020-02-10-mate-1-24-released
-  https://github.com/mate-desktop/mate-screensaver/blob/1.26/configure.ac#L950-L974
-  https://github.com/mate-desktop/mate-session-manager/blob/1.26/configure.ac#L128-L152
-  https://gitweb.gentoo.org/repo/gentoo.git/tree/mate-extra/mate-screensaver/mate-screensaver-1.26.1.ebuild#n63
-  https://gitweb.gentoo.org/repo/gentoo.git/tree/mate-base/mate-session-manager/mate-session-manager-1.26.0.ebuild#n66