While the Suica card (and its siblings like Pasmo or Icoca) is incredibly versatile, you cannot use it for everything in Japan, though it often feels that way in major cities. Suica is primarily a "stored-value" IC card for public transportation, including trains, subways, and buses. Beyond transit, it is widely accepted as "e-money" at convenience stores (7-Eleven, Lawson, FamilyMart), vending machines, many chain restaurants, and even some coin lockers. However, its main limitation is that it cannot be used for long-distance travel on the Shinkansen (Bullet Train) without a complicated pre-registration process or a separate paper ticket. Additionally, Japan is still a society where "cash is king" in many traditional settings; small family-run "izakayas," traditional street food stalls, entrance fees for temples and shrines, and many shops in rural areas will only accept physical yen. You also cannot use Suica to pay for large-ticket items at many department stores or for high-value services where a credit card or cash is expected. For the average tourist in 2026, Suica covers about 80% of daily incidental needs in Tokyo, but a wallet with physical cash remains a mandatory backup for the other 20%.