These are hard plastic shells that you can slide an individual card into to keep it safe from liquids, dents, or curling (foil curling is a big problem with Magic cards printed in the last few years)
The challenge is that the image has to be pretty high resolution digital image, and there arent that many of those for reasons Id soon find out
There are very few ways to actually lose energy counters outside of spending them, but it is possible with stray cards like Suncleanser and Final Act
Consider its card type, any effect that affects when you could cast it (such as flash) and any other effects that could stop you from casting it (such as Meddling Mages effect) to determine if and when you can do this
Being able to search for any Equipment could be abused
Common cards get reprinted every few sets, therefore they are worth pennies, with some individuals only favoring a particular edition for personal reasons