Can’t see any downside to setting as default, to me doesn’t present any unintended outcome. Seeing as though it’s not well known to exist or how to set it’s better to have functional. Users that object can disable (if they find out how…
Can also be enabled or disabled via cli, ex.
dconf write /org/compiz/profiles/unity/plugins/unityshell/launcher-minimize-window ‘false’
As far as why unsupported, says so right in linked article,
“By unsupported, I mean that functionality is “as-is” and no more tweaks or enhancements to it”
The ‘why’ of the above should be obvious to anyone who has used or followed Ubuntu since 14.04