To be honest, we may get more use out of them as sacrifice-able artifacts than for their lifegain
The more important reason Gaddock was contained was that green wasn't a natural fit for the decks that wanted Gaddock, or in some cases green was but white wasn't, and his legendary status made it difficult to go too far out of the way to get him
Commander Master is the first official set that focuses on MTGs most popular format, Commander
Decks tend not to run Gift Energy, but those that would want it tend to run 2-3 copies.
If you can take the monetary hit while its going for a relatively smaller amount of money in comparison to some of the other rare cards in rotation, snap one up if circumstances allow.
Instead of attaching the equipment to a 0/0 black Phyrexian Germ token, for Mirrodin