128GB is a Good Choice for the Pixel
1 Minute 4K Video with 30fps takes about 375MB. Jupp, 1 minute!
That means with a 32GB phone, you have about 23GB left for usage, you can only store about 1 hour of 4K video. No music, no photos, no additional installed apps, no VR apps, nothing.
23GB*1024/375= 62.805 min.
And why you might think 1 hour is long, well than think about if you edit a video on your device. It can take up to double in space.
The cloud storage doesn't help you at all. All you take needs to be on the phone first, there is no "direct storing" in the cloud. That would, away from the technically possible aspect, eat up your data on your contract in no time. You have a 1 GB plan? So that would be less than 3 minutes video.
The 128GB version instead, has about 5 hours of storage for 4k video. That means if you shoot 1 hour, you have enough room to edit the video, and having some other data or apps on your phone.
112GB*1024/375= 305.835 min.
Even though at home it will back up to the cloud, unlimited in original quality in full resolution (a.k.a. as backup :) ), you'll need some space for a day trip or your vacation. Since there is no sdcard, you have to jump through loops to make it through. 5 hours might be great for 1 day, but 1 week? While you can transfer video from your device to an USB stick via the OTG adapter (will test it when the device is here), you can imagine that with only 1 hour storage, you can't go far.
So do yourself a favor, get the 128GB version if you ever intend to use it for video recording or excessive photography sessions.