I completely agree that the file access APIs in Beaker are extremely cool, and solve a real developer problem. From a security point of view, it does slightly

I completely agree that the file access APIs in Beaker are extremely cool, and solve a real developer problem. From a security point of view, it does slightly expand the attack surface, since there could be a vulnerability in that code which isn't present in other browsers. But given the simplicity of the APIs, I think it's a very acceptable risk given the benefits. The biggest downside IMO of these additional APIs is that they only work in Beaker. If I were the Beaker team I would prioritize making them available to mainstream browsers in some way: javascript library, browser extension, webassembly... It would really help adoption if they found a way to do that.