>- Fixing your housing costs against inflation:

Any sort of serious buy vs rent calculator already takes this into account, for instance the one on nytimes

>- Capital Battery: As I build equity in my home it can become an asset I take loans against to pursue other opportunities.

That feels absolutely insane to me, especially when you consider that by the time you built up significant amounts of equity you'll have significant commitments (eg. college age kids) and/or be close to retirement. Going 3x on S&P500 might be justified when you're a new grad, but not beyond your 30s.

>- Flexibility: Should I need to fiscally downsize I can still move out and rent out. Or rent a portion either via a suite or secondary unit

How is this more flexible than the counterfactual of renting?

> That feels absolutely insane to me, especially when you consider that by the time you built up significant amounts of equity you'll have significant commitments (eg. college age kids) and/or be close to retirement. Going 3x on S&P500 might be justified when you're a new grad, but not beyond your 30s.

I don’t know about the US situation, and while I generally agree with you, home loans (in Canada) are nice for a couple reasons 1) the rate is better than you’ll get anywhere else, so you can significantly cut down on an emergency fund to stay invested (or even savings in general - e.g. you can keep invested in the market to drive your old car until it dies, get a dealer’s best price with their kickback from a bank on a new car, pay off the bank loan with a low-interest HELOC, then pay off the HELOC over the next several months) and 2) the interest on home equity lines of credit is tax deductible if used in various circumstances when you’ve already exhausted your other tax-advantaged options. (Conversely, mortgage interest is not tax deductible here.)

> How is this more flexible than the counterfactual of renting?

I read that as "similarly flexible" not "more flexible".