From what I understand (having been at that seminar and subsequent seminars at GenCon)
There will be a 'Base' set of tiles and Minis, but yes, of course, there will be subsequent virtual 'boosters' of Minis and Tile packs available for purchase.
Myself, I have all the plastic D&D Minis already, aswell as the cardstock DungeonTiles they produce. I have no need for the virtual stuff as I prefer my D&D games on the REAL Kichen Table.