Note GP didn't say "fluctuations in its asset value are meaningless", they said "Comparing the balance sheet fluctuations of a bank to its market cap is meaning

Note GP didn't say "fluctuations in its asset value are meaningless", they said "Comparing the balance sheet fluctuations of a bank to its market cap is meaningless". For example US Bank has $50B market cap, $500B deposits, and closer to $700B total assets.