No!
If  a system is properly designed and insalled, failures can be completely avoided and when a component does fail, it typically does not “crash” your entire home. You will still be able to turn the lights on and off, your security system will still function, your cameras will still record and you will still be able control the climate. That is unless one of those specific systems failed, then the rest are not affected.
When we design a system, we think about the worst case scenarios and we built fail safes into it. bu using a UPS, we assure that even during a power failure, critical systems still work.