MIPS is a must have and not a problem as nearly all the helmets being sold for road or trail use have MIPS at this point in time. For me the issue has been with the neck straps and most helmets are not comfortable for extended use. I have found helmets from Lazer, Bell, and Scott that have both MIPS protection and comfortable straps (if adjusted for best fit).
MIPS is designed to protect the brain stem and this would not be a trivial injury. Only downside is fewer organ donations by fit cyclists.