Neither Object.entries nor the File constructor are supported in IE11. WebRTC support was only introduced in Safari 11, for example. As much as I'd like to only have to support modern standards, a large portion of people use outdated browsers. If we assume 10%, we would have to either provide additional support to those customers in the form of helping them download a new browser, or cut them off completely. That's a massive decision.

While I agree that these features are well supported, they're not well enough supported to use carelessly.