I am amazed that the first thing people on this forum want to do when they get a new instrument,is to race out & hang it across the AC mains!
Then you get the reaction "EEEK!! Shock,Horror! from the CAT rating devotees.
No! No! to read 240v RMS you need to have something rated for 6000v spikes!
Most people are unlikely to be messing around on the supply side of the home or work meter box,where the supply impedance is lower,& if you get between phases,you obviously are dealing with higher voltages anyway.
What they might do is measure the mains coming into a piece of equipment,or perhaps look at a power point.
People have been doing this for many years,way before CAT ratings were even a glint in some bureaucrat's eye,& with proportionally,very few injuries sustained.
DMMs are normally handheld,which makes any hazard closer to the body than the heavy old AVOs & Simpsons which were normally placed on a bench,or the floor,so if someone is silly enough to hang the thing across 240v on a current range,there is obviously more chance of injury.
Meanwhile,back in the real world,electrical equipment of all kinds are used every day,in the home,& in industry.
When was the last time you heard of a lady using a hairdryer or vacuum cleaner having the thing blow up from an 6000v transient?
OK,these ratings are a good thing,but they are mainly an exercise in butt-saving on the part of the relevant authorities,rather than a reflection of the real world.
VK6ZGO