why does "equity" show up on my balance sheet?

[Seth Gordon]

When I set up my GnuCash accounts, I followed the instructions in the
documentation and made every initial balance in every account a
transfer from an "Equity" account.  When I generate a balance sheet,
"Equity" is one of the accounts whose value is included there.

Why is this?  I assume there is some Deep Accounting Philosophy
behind this, but since for my purposes the "Equity" account feels like
funny money, I don't understand why its value is being included along
with my bank balances, house, and mortgage.

--sethg