The guy is the lead dev of the Budgie desktop environment. Budgie started out kind of reusing components from GNOME, but Strobl has been rather frustrated with GTK and the directions it took with GTK4, for various reasons: https://joshuastrobl.com/2021/09/14/building-an-alternative-ecosystem
(The disclaimer is important, some opinions on what alternative to use changed, but the frustrations with GTK remain.)
I have zero clue about how GTK and Qt works and how they differentiate technically, but what advantages does the porting of this program have?
The guy is the lead dev of the Budgie desktop environment. Budgie started out kind of reusing components from GNOME, but Strobl has been rather frustrated with GTK and the directions it took with GTK4, for various reasons: https://joshuastrobl.com/2021/09/14/building-an-alternative-ecosystem
(The disclaimer is important, some opinions on what alternative to use changed, but the frustrations with GTK remain.)
Practically, this results in a lower footprint when installing it on KDE or other Qt6 based systems, as it will no longer pull the GTK libraries.