[brainwad]

Not much. They are moving from a regime where owner-occupier mortgage interest is deductible but you have to pay income tax on the imputed rental value of your owner-occupied home, to one where you don't pay the tax but also can't take the deduction.

For most Swiss people, who rent, it doesn't directly affect them. And even for most owner-occupiers, they never pay off their mortgages, and so the two effects currently cancel out. It's mostly a handout to rich people who can pay off a house (or inherited one).