A second bathroom is not somehting I would pay for for 2 normal people only.
But if you are 4 persons or more, then at least having a second toilet is really worth the money. Especially if one is upstairs and one downstairs and you have old people or some other way slightly handicapped people (like me with knee damage) who are really happy when they dont have to take 20 stairs each time ;)
It's a question of priorities re # bathrooms. Is a second bathroom a necessity? No - but for a lot of households the second bathroom is more important than a lot of other amenities. My other "necessity" is a garage for the car - I have lived with and without a garage, and in the middle of a Canadian winter the garage is better. No snow/ice to clean off the car - and I am talking easily 20 minutes worth of cleaning here. There are accidents every winter caused by snow/ice coming off a car that was not properly cleaned. Plus thunderstorms and hail - Ottawa had a big storm a few summers ago, and the hail damage was severe. My car is not worth a huge amount, but it is worth enough to give it some protection. Of course if I didn't have a car - but I am in the middle of nowhere, the cars go 70K on my quiet road and 80-80 on the nearest major road, so the bicycle is for fun.
A person I know had a car that was damaged in a hail. Hails are not very frequent here, especially heavy ones. The one I am talking about was ~5km away from my home and made holes in everything in a village, including roofs and walls (but seemed to have stopped in the middle at the big street, the other half of the village had nearly no damage - a really small, concentrated hailstorm).
Luckily the car had no broken glass and no holes, but it looked like a flat golf ball all over. That is really something you dont see that often...
The insurance considered it a full damage and payed the full prize of the car. That person still drives that car around (most others affected this way have gotten a new one) and saved the money. He isnt a mustachian, but that move was a M move ;)