The idea with this feat is to provide an alternative to simply adding an additional attunement slot; adding slots is a fiddly thing for a feat on DDB as they're not a bonus modifier, so while you can let non-Artificers gain 4, you can't let Artificers gain more without a bunch of different feats for each possibility.

But likewise, I'm not really a fan of feats that let characters simply do something that a class or sub-class can do, I prefer feats that provide some other unique benefit so that those classes/sub-classes can also potentially take it.

So what I settled on was this; it's a half feat granting +1 Intelligence, so ideal if you've got an odd score, and allows you to (re)attune to any number of magic items in a short rest; this is potentially a very useful ability, as you could swap out an entire magical load-out for an upcoming fight where you have some idea of what you'll be going up against, though it requires you to have some idea what that might be, and have (and carry) magic items that are suitable.

The final point somewhat assumes your DM is okay with Arcana checks as a less reliable alternative to Identify, the DC and what they tell you is of course ultimately up to them, but with advantage you can more easily justify learning about a less rare item, or getting some useful information on a rarer one (even if it's not the specifics).