I wrote an essay for a card with text this short... After playing 10+ decks, this card surprisingly gets more intriguing the same way as deciding to choose Guts, Perception, Overpower, Manual Dexterity in the starting deck.
Resources flow in this game can get pretty dynamic, such as having Dr. Milan Christopher and your cash flow now depends on your performance, you use pump cards like Hyperawareness, receiving resources from Teamwork, or aiming to play Event costing 2+ that is situational. They depends on scenarios. In these case, I need some play-testing to reveal cash problem I haven't thought about as thinking in vacuum is difficult.
But recently I played Daisy deck with no Dr. Milan Christopher and very little situational Event. Most spending will be on assets that I play regardless of situation and won't go away other than random scenario effects. That really changed both the decision to include this card to a clearer one, and even the timing to play it became clearer : Play the first copy I see.
The deck has Alyssa Graham Cost 4, Blur Cost 2, Encyclopedia Cost 2, Old Book of Lore Cost 3, and average of 1x Research Librarian Cost 2 to get one of the book. The first version I have no Emergency Cache at all, and in most scenarios it turns out I failed to setup fast enough.
Now I add 2x Emergency Cache and play again, I managed to setup most of the time. I also found that I have to play 1x Emergency Cache regardless of situation each scenario, and I will be fine. (The 2nd copy is situational and can wait.) As soon as I see the first copy, I play it regardless of not having the thing to spend resources yet. This is a huge benefit for a card that cannot be committed.
This is the most dramatic difference I had experience between including and not including it. It appears that when resource is quite static in your deck (scenario effect can't be helped), I can sprint "ahead" of my resource requirements ahead of time and stay that way. Gone the days when I was a beginner and having to play Emergency Cache to Backstab in the same turn which was really clunky, and I am now short on action to do other things.
Not many decks will be "resource static" like this one, but this deck will serve as a way to debug "how Emergency Cache works" for long time to come, if I know why it made huge difference.
Also it is important for the deck to be able to setup partially and work from there. (Not that everything falls apart when lacking even 1 piece.) I found that the smaller the cost difference of each "partial", the better Emergency Cache can give you more choices.
For example, I have Research Librarian and Old Book of Lore on hand right now. Essentially I have 2 choices to choose from : Research Librarian 2 + Encyclopedia 2 = 4, or Old Book of Lore for 3. (Just Research Librarian doesn't make things better other than poor soak, so 2 doesn't count.) The difference is 1.
If I used Emergency Cache earlier, and now I have exactly 4 resources, I got an extra choice from it (that won't be possible if Encyclopedia cost 3 instead). I can now use Encyclopedia buff to work on more resources to setup the other things.
In summary what I learned :
- Contrary to the name, you should not play Emergency Cache in real emergency. You should be able to reliably play Emergency Cache ahead of time as soon as you get it and magically get benefits in later turns, since the card has no commit icon so hogging on hand put you at disadvantage. More likely to be usable that way when your deck is "resource static".
- Having clear total cost required for the assets you must put down. My deck was about 12 ~ 14 (+7 ~ +9 more than starting 5 resources) and I need to play 1 copy most of the time.
- If you have ways to get resource based on performance such as Dr. Milan Christopher or Monterey Jack, that cash flow gets uncertain, maybe better to bet on the side of not including this card and make deck spaces, and focus on doing that resource-earning performance.
- Less usable for decks that need resources to fund powerful one-off Event that maybe too situational it ended up not getting used. Therefore playing Emergency Cache ahead of time is a risky investment.
- Varying cost between each combo set in your deck, with small cost difference between them, so +3 resources can better unlock the choices which one to setup first.