If you can cover medical costs from cash and hold for 10+ years, yes — an uninvested HSA gives up the entire point of the account.
Most HSA money sits in cash earning almost nothing. That's the single biggest missed opportunity in the account.
An HSA is the only account with three tax advantages at once: deductible contributions, untaxed growth, untaxed qualified withdrawals. The untaxed growth only matters if there's growth. A cash HSA is just a checking account with paperwork.
Invest when:
Stay in cash when:
Most custodians require a minimum cash balance before investing, typically $500–$2,000, and some charge a monthly investment fee that eats returns on small balances.
The shoebox strategy and investing are the same decision viewed from two sides: paying out of pocket is what lets the balance stay invested.