No reason at all. The bypass switch IS a single point of failure as well. Shore Micro has a solution to this in buying their more robust switch with extra power supplies and extra interfaces... But remember, you can take the single point of failure analysis to extreams-- the UPS, the rack, subsystem in the data center, etc., etc.
It is not a single point of failure, certainly not in the sense that the IPS is. If the power fails on the bypass switch, it will function just like a wire. This was confirmed by a Cisco engineer in a previous discussion:
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...