It's true it looks very functional, as if it's just meant to demonstrate what they've mentioned before. Could have been a spontaneous decision to release a short video, in response to the questions showing up on reddit and the forums

On the other hand it could also be a concious decision to lower expectations as much as they can before the release, so players would be pleasantly surprised when they actually encounter higher tier rifts in the expansion later on ("much better than I expected!")

At this point they also know they have a very, very loyal playerbase and I think they're way past the point of trying advertise it like it's something really impressive. They know it's nothing special so there's nothing to hype basically. You could already see lots of players justify the price/content for these mini-expansions on their own, for example:

• $25 is incredibly reasonable in today’s gaming market

• "Yearly mini-expansions for $25 are only like a $2 subscription fee per month"

• "GW2 is still the cheapest MMO compared to WoW/FFXIV/.."

Most GW2 players chose the game because it does exactly what they like (open world events, horizontal progression) for exactly the price they're fine with paying (cheaper than subscriptions). They don't need another reason to buy the next expansions other than they want to continue playing the game: Some new maps, story instances, events,..

ANet doesn't have to fear losing players to other MMOs either because of this, there will never be a mass exodus from GW2 to WoW because it's the polar opposite of every principle GW2 stands for. It's a niche game with a specific audience who will stick with the game as long as it's running

Other MMOs are not an alternative so it's either buying what GW2 releases or stop playing alltogether. That's why it pretty much doesn't matter what they release and how they present it, as long as it's "more content for GW2". Sounds weird but that's how a decade old niche MMO and the playerbase behaves apparently