I think? VLC is the only Qt dependency on there. That means you pull in all of Qt just to run VLC.
If you are making a default install, it is best to only include one or the other toolkit for a lot of reasons:
* Consistency. Gnome and Qt apps, even when themed the same, have different UI metaphors, especially modern GTK3 apps and Qt Quick apps vs everything else.
* Performance and memory. Central to making a fast, responsive, low resource using OS is sharing libraries. Having all your software using the same hot toolkit rendering code paths means - optimally - better cache coherency and - generally - lower ram usage from not having to pull two toolkits into resident memory at the same time.
* Install image size / hard drive disk usage. Full Qt (including webengine) takes up at least 400MB of space. That is both on the iso and in the final install. That isn't a problem for average use cases, but there exist both bandwidth limited and storage limited scenarios where you can still run a modern desktop to consider.