The biggest impetus for us was peace of mind for the wife.
Since moving in here in 2010, I don't think there has been a year without at least one multi-hour outage & a number that have exceeded 12 hours. We had managed pretty well with the portables (a 5.5kw porter cable that lasted 20 years, followed by the present 7kw champion dual fuel), but it has never been a process the wife felt she could comfortably (or safely) do alone. Doing without was not an option, we depend on the well pump for water and have multiple freezers and refrigerators.
The whole house option meant no picking and choosing which circuits to include and that both heating & cooling were covered (portables kept the fans & furnace available, but no AC). Plus there is the convenience factor of not having to be up at 4AM to refuel or set up the generator & its' shelter in a dark rainy (or snowy) night! We are both retired, don't have a lot of expensive hobbies (not counting tractors

...) or feel the need to trade vehicles that often, so resources were available (and you can't take it with you!).
This is how it looks with everything filled in:
The dark area is were the exhaust fan cooked the grass. Probably need to do some marble chips or stone there ...
Nick