My in-laws learned this the hard way after a total loss fire. Their insurance covered the current value of the house, not the cost to move/replace it in a total loss scenario, so now they have a big mortgage for their new house when the old one was nearly entirely paid off
50% of a seven-figure number is still at least a six-figure number. Very useful, definitely not essentially useless. If you disagree, please give me six figures, which you apparently don't need, so I can test the theory.
Absolutely. It is also never a bad idea to have at least 6 months in expenses saved up in cash for emergencies. And another 10 thousand to keep an attorney on retainer.