I actually prefer CLI. GUI store such as the ones incorporated in Zorin OS or Pop OS are cluttered and sometime confusing. Now let's say I want to install X app, so I go on and search for it in the said store and I find 3 results for the app I search for. One is flatpak, one is snap and the other is the one from the repository. I do not want that and I prefer the store to only have the apps available in the official repositories.
As other have mentioned, it is very simple to head to https://flathub.org and search for the apps you need and copy the installation command and paste in terminal. Anyway, terminal will show you what is really going on, which is not the case when using a GUI. If you install a flatpak app for the first time, it will take a very long time and most user would think that installation is stuck.