Dont get me wrong have looked at ER40 for specific work holding rather than revisit the 5C route.
For whats its worth any engineering type company that produces by the batch needs the minium of down time. ie parts or tools replaced as quick as possible needing no setup to continue.
In this respect ER just dont cut it unless for specific applications or naive to extra labour costs and downtime.
Theres masses of other work holding setups that fit the bill, Tormach, Weldon, other quick release setups along the lines of these (brilliant cutters by the way). https://www.secotools.com/#article/m_6890 Twist unlock, pull and out job done, 5 seconds to replace and no resetup. Idea is to replace a broken tool with minimal setup ie same cutter in to a stop = ready to go and repeatable.
Bottom line cnc ers take a lot of shallow depth of cuts at faster spindle and feed rates than any manual users ever would tehrefore substantially reduced risk of ER cutters dropping during a cut.
Looking back all the problems i have encountered using ER types have been down to vibration and or tool wear. ie blunt milling tool can develop a chatter at every flute which may result in felt or visible vibration. With cnc thats just programme fed with no user feel as to whats actually happening, if done manually the operator would instantly or should know and make amends.
I buy in a fair chunk of whats regarded as top quality German made high value items to modify. Each batch measures substantially different whether that be thread sizes or just general maching and bore sizes. Can be 0.22mm difference where 0.06mm would be poor and your working to less than that.
You can put that down to machine setups, programmes the same.