It is more dangerous to run RepServer with the RSSD residing on ASE. Why? If the ASE RSSD goes down unexpectedly, RepServer doesn’t immediately know this, when it does, it dies … HARD. Restarting both ASE and RepServer, you might discover that your stable queues are partially scrambled or missing data.
This was brought to the attention of RepServer Engineering almost a decade ago (by a certain fellow named of Zhong) but no fix has been made… "it is not a bug".
The ONLY advantage of running RepServer with the RSSD on ASE is if you have multiple RepServers on the same box and you wish to save on a bit of administration. Basically it is the ease of use.
So, put your RSSD in ASE if you must, but you’re probably better off with the embedded RSSD.