The game's design and mechanics have continually adapted to keep the gameplay fresh and exciting
As you can imagine, being forced to buy books to get one card did not sit well with everyone, resulting in the series stopping after 5 books and this particular methodology of implementing promotional cards wouldn't be used again
It can be used not only in a defensive way, clearing annoying ETBs or powerful abilities, but also in an offensive way, making Deaths Shadow 13/13 or Kroxa, Titan of Deaths Hunger a two mana 6/6
In fact, I would go so far as to say that you'll probably end up casting this without your commander in play more often than you will with him there, which is saying something since you'll have the temptation of an Ancestral RecallAncestral Recall telling you to hold it
This also applies if 1 of them can no longer be chosen
The best +1/+1 counter Commander cards in MTG arent always the ones that put counters on things, but the ones that make sure you can get the most out of it when you do so