Of course it matters, losing wealth matters even if it’s not ‘crystallized’ by selling. Your options are much more limited. Fixed low rates are only helpful so long as you can maintain sufficient income which in a severe recession becomes more difficult. Additionally if the property continues to depreciate it may be wise to cut one’s losses go bankrupt and start over. Historically those who held on were bailed out in short order by the inflation of subsequent bigger bubble. The size of this recession may get too big to bail out so we could enter new territory. Or maybe we kick the can down the road again, I don’t know, but it’s a risk.