There are surges, low voltage, and high voltage caused by miswired power pedestals and failures in power pedestals. The progressive unit protects from all 3. Someone saying surges are not an issue so don't buy a protector is like saying I've had insurance on my house for 20 years and never used it so I cancelled it. Just last weekend we had very low voltage at our site. Progressive unit shut down our power. If we would have run the air conditioning very long with the low voltage, 98 volts, it surely would have damaged it. Fortunately it wasn't that hot yet.
BTW, point of clarification on the bypass switch. The bypass switch only works if the unit is not damaged as might happen if a big lightning strike hits nearby. Most of the parts in the unit have to be functional for the bypass switch to work. Being able to physically bypass it if trouble is good planning.
There are 10 types of people in the world.
Those that know binary, and those that don't.