Despite the Pixel 4's multitude of new camera chops, you can still reproach it for a few missing features. It lacks a wide-angle camera, it doesn't have autofocus on the front cam, and Google still limits 4K video capture to 30fps. The company has clarified the reasoning behind the latter.
In an answer on Twitter, Google said most users stick with 1080p and it's better to optimize that than allow a 4K 60fps mode that eats up storage.
Hi, Pixel 4 supports 4k video recording on the rear camera at 30fps. We find that the majority of users stick with 1080p, so we focus our energy on improving our quality in this mode, versus enabling a 4k 60fps mode that could use up to half a gigabyte of storage every minute.
— Made by Google (@madebygoogle) October 20, 2019
Personally, I stick to 1080p, regardless of what my phone offers, mostly for that same reason. A few seconds of video already take up several Megabytes of storage, and I don't have the luxury of a fast or unlimited connection (even at home) to upload files exponentially larger than that. Keeping them on the phone and backing them up to a drive every few days to empty storage isn't practical either. 1080p is just fine for me.
But we're not all the same and I can understand users' frustration. The limited storage issue is Google's own doing. It should've fixed it by offering 128GB as the minimum option for the Pixel 4. If it was worried about Photos cloud space more than local one, these videos will be compressed under the free High Quality tier, or will be paid for by users who choose to upload them at full resolution.
We think the unsaid reason is that recording 4K at 60fps requires resources on the phone. Even at 1080p, our own Artem saw choppy behavior in the camera app on his Pixel 3, so imagine what would happen at 4K 60fps. It's doubtful the jump from 4GB to 6GB of RAM would mitigate that, and the experience wouldn't be smooth for many.