Generally there are a number of improvements in survivability and redundancy on military ships vice civilian ships in grey paint. WRT the Asterix vs JSS there are a few:
-Asterix has a single shaft line, engine, rudder. JSS will have two of each of those.
-Asterix has less compartmentalization than the JSS, thus any damage it does sustain is potentially more disastrous as fire or flood can spread further more easily.
-Asterix has no ballistic protection, thus smaller caliber weapons can do more damage and explosions do more damage.
-Asterix won't have self defence capability aside from some 50 cals for port security, where JSS will have hard and soft kill measures for many different threats (Nixie, ECM, MASS, CIWS, etc..).
-JSS will also be able to operate in a chemical, biological and radiation environment, Asterix won't.
-JSS is edge ice capable, (Asterix might be but haven't found a reference that says it is so assuming no).
There are other differences but I think you get the picture. Not to say Asterix isn't a good solution to a problem we have. I'm not opposed to a high-low mix for the AORs. Asterix can do a ton of good work in many ways where a proper warfighting AOR isn't required.