Is this true? Should I invest in the 240V surge protector and cable(s)? Just curious...
Any recommendation that also does not say why with numbers is often a myth or scam.
If using a 240 volt power source, then all cables must already be rated for that voltage.
What does a protector do? Protector can make damage easier if located adjacent to a miner. Protectors that are effective never do protection. Those proven devices only connect a surge to something completely different that does protection - single point earth ground. Protection is where hundreds of thousands of joules are harmlessly absorbed.
Best protector for all 120 and 240 volt appliances is located at a service entrance with a low impedance (ie less than 10 foot) connection to earth. If even one miner needs that protection, then everything in a house needs that protection. With numbers that even define protection from direct lightning strikes. A protector is only as effective as its earth ground (which obviously is not a wall receptacle safety ground). And typically costs about $1 per protected appliance.