Though it hasnt been explained in detail by Wizards of the Coast, it seems fairly obvious that their licensing deal with Marvel/Disney only covers them for printing a set physically, and not using the comic book characters and settings digitally
Neon Dynasty saw the return of three popular mechanics, with ninjutsu allowing you to cheat creatures into play if the thing they replace is unblocked, channel allowing you to discard cards for effects, and enchantment creatures
Another downside of Portable Hole comes right from its types: being an artifact in an Urzas Saga meta, means that hate cards are plenty, so you dont want to play a removal that dies to cards such as Kolaghans Command
The first is that it offers a huge array of options, you can always tell when someone has a Chrome Mox in their opening hand simply because it is the only plausible reason they could be thinking for so long
Scrapheap Scrounger gives aggressive decks a great way to apply a long-term stream of pressure on controlling opponents that are trying to win the game by killing everything