It was explained to me that obligatory fire insurance is sometimes mandated by a canton to ensure that everyone has insurance cover for the almost universally unaffordable losses associated with a devastating house fire. It is a rare event, but when it happens, I'd guess that that at least 95% of the people to whom it happens can't afford to replace everything they lost.

It is far more common for people to have regular break ins, (big-screen TV, computer, jewellry, etc.) but these are considered "affordable" losses, and the canton will not mandate that everyone have private insurance, it is a personal choice. Hence there is only mandatory insurance for relatively rare but potentially very costly events, and the optional type is for more common but less catastrophic events.

This certainly doesn't explain why in Vaud such insurance can only be obtained through ECA and not your regular insurance agency, but I do think it makes sense. Realistically, I won't miss 76.- CHF a year, and in the event I ever need this insurance, I'll be glad to have it.

HM