The Energy Scale of Artifact Tokens
Since their big debut in shadows over innistrad, we've gotten a number of sets where one of that set's mechanics is an artifact token. These artifact tokens all have some intrinsic use- usually but not always requiring sacrificing them. Often, though, in addition to this intrinsic use case, there are some number of cards that are designed to use that artifact token for an alternative purpose. The more the player is expected to use a given artifact token for alternative purposes, the more that artifact token approaches being energy.
The energy mechanic is the purest form of an alternative resource in the game. Energy has practically no intrinsic value. If you play a card like Attune with Aether in your deck with no other energy cards, the energy you gain from it is going to do nothing. The only value of energy is in cards that specifically care about it. This means that designers of a set using energy have to consider the "energy economy"- what is the value of an energy counter compared to other resources? The more an artifact token has alternative use cases, the more it has its own alternative resource economy that the designers must consider. A vanilla artifact token with nothing but a subtype and no inherent ability- something very similar to Farid Enterprising Salvager's Scrap tokens, but with a subtype that could be specifically refered to by other cards- would be used in very similar ways to energy, as a resource for cards to care about and little else. The main difference is that there are far more generic artifact and permanent synergies than there are generic player-counter synergies, and so even with no inherent use case, Scrap tokens could not be given out as freely as energy counters are. The economy is less self contained.
Some existing artifact token mechanics are closer to this hypothetical than others. Food is at the far end of this scale. Any set with a Food theme tends to give lots of alternative use cases because a) gaining 3 life for 2 mana isn't worth a lot and b) if Food is used too frequently for its intrinsic use case this slows the game down in a way that isn't particularly fun, so providing an alternative helps avoid this negative result.
On the opposite end of the scale, I would place Junk tokens. Junk has very strong intrinsic value, which means it cannot be given out as freely as some other tokens, and because it is less common it is difficult to build an alternative resource economy around it. An effect that costs "Sacrifice a Junk:" would have to be strong to offset what the player is losing out on. (Though admittedly, many pre-op trans people would not see sacrificing their junk as much of a cost at all.)
Every artifact token exists somewhere on this scale. Landers, Maps, Mutagens, and Powerstones exist closer to the Junk end; their effect is desireable and well costed, and there are not many cards that use them for an alternative resource than the one they intrinsically provide. (Of course, any artifact token is subject to generic artifact synergies such as the cost of sacrificing an artifact, but because these kinds of synergies are universal to all artifact tokens, they are less relevant to this kind of comparison.) Blood exists closer to the Food/Energy end of the scale; a more significant portion of its value as compared to Junk, at least in its debut set, was in cards that wanted to sacrifice it for other effects. It is certainly closer to the Junk end than Food though, because its intrinsic use case is a bit more valuable and is less problematic in large doses. Clues and Treasures exist closer to the middle of the scale; their intrinsic value is more than food, but not so high that it is difficult to use them for alternative effects.
So if you are a custom magic card designer making a set, and if you are using an artifact token, think about where you want it to fall on this scale. How much is its intrinsic effect worth, and how often should your players be using it for that effect vs an alternative? The answer will have important ripple effects on what else you want to be doing in your set. Having multiple alternate-resource economies in a single environment, for example, is quite complicated, so a set probably shouldn't have both Food and Energy as a major theme.
