When developing/editing any FTVSE application you are actually working "live" within the FTVSE Server since there is only one "tier" of FTVSE application level; the FTVSE Server is "serving" the application(s) to all the configured Clients.
FTVME, as you are probably very well aware, is using a two tier application approach; there is the Development Application, where you are designing and configuring and then there is the Runtime Application which is a "streamlined" compilation of the Development one; the Runtime (.mer) is to be individually deployed onto the PV+ graphic terminals.
There are both advantages and disadvantages for either FTV "flavor".
Since you are familiar with the ME, you will find a lot less cumbersome to create/develop/edit a SE application; any change could be real-world implemented by simply picking "Save" from the File Menu of the FTV Studio software; no need to compile/download.
Of course you could also just simply disable the entire system if you make a major mistake.
Another major SE/ME difference is that FTVSE applications are not "portable" the way the ME Archive (.apa) type files are; you will need to be Online with the FTVSE Server in order to work on an application; you cannot work Offline and then simply compile/download the way ME does it.