Without p2p you can't trade your coins to Fiats except maybe you know a vendor that you can be exchanging coins directly with. Sometimes, i used to wonder how we would have been converting our coins to Fiats if p2p platforms were not there. When i was new into bitcoin and i only know about wallets, i was like how can i convert the coins in my wallets to Fiats, it was then i got to know about centralized exchanges and Binance was the first CEX i was introduced to, at that time they were still performing p2p transactions for the Naira before they had issues with the federal government which led them to delist the naira p2p from their platform.