Just my two cents here, but I do also think this applies to Siege. And not just 'sort of'. Players from every shard come to these events, so they are a great time (imo) to advertise that Siege exists, and does have active players. To my my mind, it is like potentially recruiting from ALL shards, all at once in one place. Saying on Trammel that they claim their reward on Siege is free advertising for my favorite shard! The more Siege players that attend these events, claiming their prizes on Siege, is good for Siege.
A lot of people have this notion that Siege is nothing but trash talking murderers and thieves where you cannot take 2 steps without being slaughtered. Sometimes they are right

But most of the time, we're the best shard EVER, and I wanna flaunt it every chance I get.
Bring on the commercials, Drakelord!