Coinbase's trust case is the strongest of any US retail exchange. Audited SEC financials, ~98% cold storage, segregated funds, and crime insurance on held assets give it a disclosure stack that most peers can't match. Free ACH and instant RTP cash-out up to $100,000 make the fiat experience frictionless for US users. The cost is the persistent caveat. The simple-buy screen is expensive, often 2.5% to 3.5% on small orders once spread is counted, and most beginners never switch off it. Advanced Trade brings fees down to 0.00%–0.40% maker and 0.05%–0.60% taker, which is competitive. Coinbase One removes simple-trade fees within a monthly cap for a subscription. Neither option is the default. Use Coinbase if you want the most regulated US exchange and plan to use Advanced Trade or Coinbase One. Skip it if you trade frequently on the default screen and won't switch.