While these types of effects generally come in all sorts of varieties, here are a few things to keep in mind: Abilities will only change one set of types when changing subtypes
Mono-Black can make a ton of mana, so you can easily pay its Commander Tax a few times to get multiple sacrifices, and he just cost's four initially
It turns a simple pull into something special and memorable
It does have the downside that you cant bounce your own cards, but I find myself wanting to do that less often in cEDH than I would in limited, for example
Ultra Shiny is an even rarer version, and unlike the Shiny version, instead of stars appear squares with a directed animation when the Pokmon goes into battle
However, note that you must choose a minimum of 1 Digimon with a play cost of 15 or less