So, my worry about the VTT isn't that it will force deceptive micro-transactions like Fortnite or anything like that. And I think the "pay to win" alarm is ridiculous; D&D just doesn't work like that and if they implemented something like "pay $$$ so your fireball does extra damage" they would be destroying their own game. WotC are not idiots, nor have they ever been malevolent. So the fear them suddenly becoming malevolent idiots does not keep me awake at night.
My one concern, and it may not even be a concern, is that the VTT is likely to put more of the financial burden on DMs who, as WotC acknowledge, already provide the overwhelming majority of purchases for the game. Take, well, me for example. I spend a freaking fortune on terrain and miniatures. And I am not complaining - it's a hobby that I am passionate about, and I love painting the stuff, building sets, etc. But the VTT has the potential to create a lot more "me-s."
Imagine being able to purchase all the maps in digital form and populate them with digital characters and monsters, similar to what we saw in the preview. And imagine that it was easy to use, and you could then use those resources to make your own maps. Maybe you've always wanted to do that the old school way, like many of us did, but the cost was prohibitive. But for, say, $50, you can get all the digital terrain tiles and creatures to run Tomb of Annihilation, or anything else you want to build with those resources. And then adding all the Rime of the Frostmaiden stuff for another $50 starts to look pretty good...
And that is exactly what WotC is proposing, though they haven't come close to announcing any price schemes yet.
This actually sounds pretty great to me. But my concern is that this does not remotely address the issue that WotC raised: that the game primarily monetizes DMs. I think the VTT is another thing that DMs will mostly pay for - cosmetic upgrades to character avatars will be a drop in the bucket compared to the cost of digital terrain and miniatures collections.