I'd have to provide an alternate view of this card, and endorse that it's actually a very good card in the right deck and investigator, which is a primary rogue fighter.

If you're playing Tony Morgan, one of the strongest investigators in the game, as your primary fighter then this card becomes invaluable, particularly as your first upgrade. +2 fist icon every turn (the resources on the card replenish each round) along with Tony's natural 5 fist icon means you're succeeding most fight skill checks. As rogue, if you're playing staple cards such as .41 Derringer, Lucky Cigarette Case, Quick Thinking, then the +2 fist icon is going to be important for you to trigger the conditions on those cards.

This card also synergizes well with Tony's signature cards Tony's .38 Long Colt and Bounty Contracts, since you're quickly generating more resources than you can use, so it's good to have a resource dump card like Hard Knocks to utilize your accummulated resources. Add to it the fact that the card is not unique and you can have two SLOTLESS copies of this card on the table at the same time means you can have a free +4 fist icon to any fight skill check you want PER TURN and more if you decide to pump your own resources into the card's ability.

Lastly, the card's ability to boost foot icon is nothing to sneeze at. Since Tony is at a measly 2 foot base (a rarity for rogue players), you can easily boost his low foot score with Hard Knocks to get him to pass his foot skillchecks for treacher cards such as Grasping Hands. Also, I added a pair of level 1 Lockpicks to my Tony Morgan deck, and I can boost Tony's foot icon with this card to ensure both success with the investigation as well as preventing the lockpick from losing a resource by succeeding by at least 2.

Solid card for the right investigator, a rogue who is a primary fighter.

Out of all the resource dump/pay-to-win playable assets in its suite of cards (Hyperawareness, Arcane Studies, etc.), I think this upgrade should see the least play for two reasons:

1.) Resource economy. I saw this mentioned in passing in a comment on a Hard Knocks (2) review, but wanted to more strongly state it here since level 4 would be more of a commitment and restricts it to mainline Rogues (watch there be some investigator that takes Talent assets up to Lvl 4 or something): Rogues have the easiest access to resources; don't underestimate that. Not just in class cards, but even in investigator abilities for some of them. If you're so strapped for resources that you need a resource discount on this card, as a Rogue, then you'd be better off investing in something that gives you more resources or a greater effect than just a +2 each turn. After all, you have 4 XP to burn.

Sidebar: Personally, I would even posit that Hard Knocks (2) isn't worth the purchase. It does have much more off-class potential, but so do a lot of resource-gain Rogue cards. The argument could be made that you're buying resource discounting in the same card slot with (2), and when it comes to off-class uses of pay-to-win cards, you can be using them for any number of reasons depending on the economy and card slots of your deck; I don't want to be stringent on that, but honestly I really don't think it's worth the XP in my opinion. Not as strong an opinion as for Hard Knocks (4), though, which brings me to....

2.) The price tag. Having replenishing skill buff every round is really nice, but as a Rogue, you have much better and much more EXPENSIVE XP buys than this to consider. The vast majority of Exceptional cards are Rogue cards, and only two of them (standard disclaimer: "as of this review") offer multiple versions for incremental upgrading, so you'll be needing to save and ration XP if you're interested in their purchases. Even apart from spending XP for resource gain, there are many other (sometimes pricey) cards that utilize resource hoarding/spending better than a Lvl 4 card that gives you 2 extra "resources" per round. XP budgeting is important in general, but especially as a mainline Rogue.

I'd steer clear of this variation of Hard Knocks. The upgrades to this suite are meant to save you resources and make the card trigger more often as a result, but this is just the wrong class for this sort of an upgrade.