Why Can't You Play Games on TradeCardOnline? It's a Marketplace, Not a Gaming Site

TradeCardOnline is a marketplace for physical trading cards—not a gaming site.

It facilitates buying/selling/trading cards (Magic, Pokémon, Yu-Gi-Oh!, sports). No game engine, no playable matches.

Where to Actually Play Card Games Online

• Magic: MTG Arena (PC/mobile), MTGO (PC)
• Pokémon: Pokémon TCG Live (PC/mobile/tablet)
• Yu-Gi-Oh!: Master Duel (PC/console/mobile), Duel Links (mobile/PC)
• General: Tabletop Simulator (Steam), LackeyCCG, Untap.in (browser)

Use TradeCardOnline for cardboard; use the above for digital play.