I know, it wasn't initially clear to me either. nostr:nprofile1qqsr7acdvhf6we9fch94qwhpy0nza36e3tgrtkpku25ppuu80f69kfqpr9mhxue69uhhyetvv9ujumt0d4hhxarj9ecxjmnt9uq3zamnwvaz7tmwdaehgu3wwa5kuef0qy2hwumn8ghj7un9d3shjtnyv9kh2uewd9hj7eyerqr and nostr:nprofile1qqsyvrp9u6p0mfur9dfdru3d853tx9mdjuhkphxuxgfwmryja7zsvhqpzamhxue69uhhv6t5daezumn0wd68yvfwvdhk6tcpz9mhxue69uhkummnw3ezuamfdejj7qgwwaehxw309ahx7uewd3hkctcscpyug had to break it down into simple / small words for me, and I'm still not sure I fully understand it (so take what I'm saying with a grain of salt).
Apparently, it works like this because the "Mailbox" model is a relatively new concept, and not all clients support it. General relays is the "old school" Nostr way.