A gentle reminder that this is statistics, not certainties
If you have a $30 player and a $1 player, you can always drop the $1 guy to make room for a hot young prospect
The only reason Zulaport Cutthroat beat out Blood Artist is that it is a 1/1 rather than a 0/1, and has three creature types that can all work well in black Commander decks, over Blood Artist's lone Vampire typing
A much more powerful example is Warren Warleader, which can make attacking tokens or pump the board when it hops into combat
Either they have random effects, making them hard to build around because you don't know what they're going to do, or they have the potential to not work and make you waste or lose the resource
The best strategy I have heard is to Guard your Uxies, attach Energy and just keep doing Psychic Restore to the Machamp, who has a +30 weakness to Psychic