Earlier quoted context omitted.
You are paying property tax on that money you are using for that HELOC. If I bought a house at $300k, I owe $250k and house is now worth $750k the County will be slapping me with $10k/year property taxes whereas before I was paying like $3k. My gains are realized each year via property tax assessments :)
> My gains are realized each year via property tax assessments This strongly depends on jurisdiction. In many (today I learned, not all) assessed value is explicitly different from market value.
With "unrealized" stock gains you are doing just that - hiding ownership so you don't have to pay taxes while enjoying the perks of the ownership when it suits you