If you drop Get Ready in a random deck, it is usually disappointing, all it does is let you use up an ally one round earlier. And while this effect is sometimes useful, most random three hit point allies get used up quickly enough anyways and there are likely to be other cards you would rather put in your deck instead (assuming you have a decent number of expansions), so most of the time I skip this card.
But there are lots of specific situations where this card is more practical. It is possible to build decks with enough extra ally hit points and ally healing that you actually can't go through your ally hit points fast enough to make maximum use of them, and this card gets close to giving you just a free ally action. If you spend resources to pump up 1 ally temporarily for a turn (the Vision for example), you can use this card to get an extra use out of that on the same turn. Or in some cases you can do the same thing with a suicide power like Goliath. Another option is to Inspire Black Cat, then use this card as an absolutely free two damage. I've yet to create a deck myself where I thought this card was amazing, but I have created decks where it was interesting and sometimes useful and provided some variety to the deck.