Benefit's Boi-ing is one of the most popular products in their entire lineup. These are billed as concealers that double as shadow bases, but empirical anecdotes from users seems to provide the opinion that while these are great as concealers, their use as shadow bases is much more limited. Still, these are quite popular, so there is something to them.
As is usual in most parts of Europe and Asia, Benefit didn't bring in the darker shades, so 03 Deep is missing. But here are swatches of 01 Light and 02 Medium:
01 Light would probably be my shade if I had to pick a colour from the range, and I'm about NC20. 02 Medium looks to my eye to be around NC30-35, maybe.
One of the reasons why Boi-ing is so popular is because it's very pigmented. So it's probably useful for concealment of blemishes and undereye circles. These swatches were probably a couple of swipes, and you can see that the coverage is excellent. The consistency and texture of the concealers was also good - they strike a nice balance between pigmentation and a texture that glides.
So do you need this? Well, for one, 3 shades out of a gazillion human skintones means that not everyone will be able to find a match, which would make the question moot. But if you do have a match, and want something pigmented, then these are worth looking into. But of course, weartime would vary from person to person, so that may be the deciding factor in the end.