If Travel Preparations targets two creatures, and one of them is an illegal target by the time Travel Preparations resolves, you'll still put a +1/+1 counter on the other creature
Thats an outrageous bit of value attached to one of your characters and it also protects you against the classic one-two punch of the meta defining ruby-amethyst control deck of set two, which would wipe your board with Be Prepared and then answer the first character you play with a Lady Tremaine which would force you to sacrifice it
Heroes and villains each got ample support, incredible commanders like The Unbeatable Squirrel Girl and Bruce Banner // The Incredible Hulk are here, and there's even a cycle of decent lands to open
That token isn't "created" and won't interact with abilities that care about tokens being created
The deck has a much wider appeal, though, with a strategy that leverages powerful songs and flexible characters
Without an established agreement, some overzealous player is going to get carried away and buy more cards than everyone else and always win