Sure, the reason is quiet simple. For Clients which dont have a possibility to decipher like vlc, or Android SAT>IP Clients, it is sensfull to decipher on the serverside, but Clients like a VDR can do this better and proper by themself.
Therefore, i think, it could be useful to implement something like a usermangement who makes possible to exclude Clients from deciphering, maybe by Name and/or IP.
Example:
If User-Agent = vdr-satip && IP = 192.168.1.55 ,then do not decipher.