I would say the level 0 Cleaning Kit is one of the best cards of Hemlock Vale, sitting in the relatively uncontested Accessory Slot and adding huge value to anything with slightly scarce ammo (Lightning Gun, Shotgun, Old Shotgun and especially the Ornate Bow) and also to other off-class cards which use supplies (Fingerprint Kit, Chainsaw, Strange Solution, Thieves' Kit). So, does the upgraded version perform quite so well? For me, not quite.

At one extra supply, the Cleaning Kit (3) won't go much further than it's level 0 counterpart - and usually decks built around Cleaning Kit in general will have other means to make supplies go farther, such as Emergency Cache ••• and occasionally Contraband. The main aspect of this therefore is the utility of the +2 boost, which is one per turn given it exhausts the Cleaning Kit.

For over-succeed gun builds making use of a shotgun (Old or otherwise), most will use Custom Modifications. In these cases, the Extended Stock upgrade achieves the same effect as a persistent boost and for just 2 XP rather than the 6 XP you would use on two copies of Cleaning Kit (3). What's more, Custom Modifications is also a candidate for the perennial Guardian-enabler Stick to the Plan, making it dramatically more reliable. Even discounting Custom Modifications, cards like Enchant Weapon will usually provide a bigger one off boost. The only niche it becomes useful is on Guardians who can't take high level Guardian cards (and so can't access a fully tricked out Custom Modifications or wouldn't be keen on guns anyway - Parallel Roland Banks for the former with an Old Shotgun and Wilson Richards for the latter). Even then, 6 XP is a lot to spend when the base Cleaning Kit is a level 0.

On the side of generically providing a boost, I'd say other cards often do this better. Girish Kadakia provides fat soak with an unlimited +2 per turn boost, and costs just 1 more XP than the upgraded Kit (and you can still keep the level 0 Kit for its supply utility alongside). Likewise, Well Prepared can provide stronger boosts if used well. Even the humble Reliable accesses a persistent +1 for the asset you want to be using at much less XP. While Girish and/or Well Prepared are extra assets you need to get into play, Guardians love Ever Vigilant on Stick to the Plan - so additional assets typically do not have the same opportunity cost usually that they do for other classes.

EDIT: People say this is a false equivalence because of the cost to source the card and get it into play and the resource cost (which I thought was too obvious to mention). It's a cost I would take personally as the boosts on the other cards are more flexible, just flagging the discussion below.

Overall, I'd say there's vanishingly few reasons to use the upgraded Cleaning Kit over its level 0 counterpart - there's just better ways to get boosts and most of them cost less XP as well. What would have made this better would have been adding more icons to the card (e.g. having it as ) so it too could have been a target of Well Prepared, but even then I'd still say it doesn't offer enough for its price.