Todd, it may have been a bit of both. The series is created by Clint at GPK and Wacky Warehouse, the there were packs and special sets sold at booths. A major hook was to support artist participation, so there were promos exclusive to artists and cards configured for signing, and sketch cards for sale by the artist if not in packs.
It started following the 2016 GPK Con, and in the beginning had a focus on David Gross, thus the name.
Here's
a news release announcing the 2019 edition. I assume 2020 might have been largely virtual, but it may have gotten in under the wire for mid-March. They renamed it the Gross Xperience.