There was a post a few days ago telling a story about some major damage in an RV park from lightning and the poster survived it due to having a Progressive Industries unit in play. I have a portable unit and would not connect without it. I have even used it to test pedestals for others to see if it is wired correctly, although they would not have protection afterward if something went awry.
Look at it as cheap insurance from having to replace a aircon unit, refrig, microwave etc.
"I might be movin' to Montana soon..."
2013 Eagle 29.5RKS
2013 Ford 6.7L diesel F350