Well in my fact my scl rpm aims a different goal than @giacomo 's one. I want to be idiot compatible (and I’m proud of that), giacomo is more on the developer’s side.
If nextcloud brings a new rpm with N11, then the template of apache must be adapted to use the php56 of nethserver-rh-php56-php-fpm, and this path is scriptable by the software center, because the repository used is the centos scl, enabled by default.
If you install manually a web application (whatever Nextcloud or not) my scl rpm will ease your installation since a lot of php{56,70,71}-php-* are installed from base and you need a mouse to click. However you can also use it with a rpm based installation but firstly you need to install the remi repository since we use the remi-safe branch (no upgrades of existent other rpms). The remi installation is not scriptable 
This said, I’m not sure that to upgrade a rpm by the administration panel is a good idea, a rpm takes care of the name of files, and after a web upgrade you can add files which were not added by the rpms, then when you will want to remove the rpms, probably you will have many orphan files. Nevertheless, if the developers offer this upgrade path, I hope that they thought about this.
Concerning nethserver-php-scl (my rpm) the choice to go with remi was done with el6, but sure that now we could go with the centos scl repository php56 php70 (enabled by default yes), even so we lack php71 and many many many php{56,70,71}-php-* that remi takes care to bring in his repo. Quite all rpms you find in centos repo are done by him, however the politic of security/quality/… gives time to wait/loose.