Olight has a follow-on product that is a bit larger, hardly noticeably brighter, has a slightly bigger battery, and charges via USB-C. But the name of the game for a keychain light is size, adequate brightness, and ready to work when you need it.
Olight is more and more focused on rechargeability in its products, and has eliminated earlier offerings like the Baton S2 with magnetic base for the Baton S2R and now Baton 3, rechargeable-only. There is a problem with that, in that they eliminate using Lithium Iron primary cells and similar technology that have shelf life over 10 years and operate well below freezing temperatures.
This keychain torch is adequately small for the role, and its two brightness levels are a good fit as well. Its Micro USB rechargeable battery capacity is likely adequate for the role, but the issue will be how long does this Lithium Ion battery retain charge for months. A keychain light might go several months before called upon to work.
Only use will determine if if it does.
It's for this reason that I'd prefer a single AAA light and using a Lithium Iron ("Ultimate") in this role. Olight made a miniature light that was a promotional version of their X9r Marauder. This used a tiny CR425 Lithium pin battery made for fishing bobbers. It was close to perfect for a keychain light.
My primary application is for a small light to hang on my hammock ridge line with an S-biner. In that role it does well given it is charged before heading out, and the trip is only a few days.
For a longer trip, there's always the cell phone recharger along to charge it.
Bottom line - Adequately small, reasonably priced, effective in use. The question is charge shelf life.

Certainly the most light for the smallest package. Make sure to put it on a key ring or you will lose it in your pocket. The on off switch is well thought out and starts low then goes high. Better than the ones that start with blinding light then let you dial it down.

Just a great light. Everybody should get one. Thanks!

There are a lot of keychain lights on the market, but this one may be the best. High build quality, plenty of light output, smooth beam quality, and lighter weight then other metal keychain lights. The twist control is very smooth and turns the light on/off without intermediate flicker, unlike another brand with similar interface. My only complaint is the battery is not replaceable, though if it had been, that would have made the light larger. Of course at the low price of this light, its not so bad to just buy another when it will no longer take a charge. I'm already a "return customer" on this one!

I recently purchased two of these for my wife's and my keychains. They are really easy to charge and use. Lightweight and small so it doesn't add a lot of bulk or weight to my keys. The two brightness modes are perfect. The 150 lumen high mode really is bright!! I'd highly recommend these for anyone needing a lot of light on a small package.