This trick can be very useful i many situations. For example, one might have to suddenly free up space to take more pictures while on vacation. Or one might have to free up space to download PDF file for work. This trick is better than hunting down apps to delete.
I was there before... ZERO mb free space. I wanted to take more pictures, but I couldn't. When I was looking at which apps to delete, I mistakenly hit "update all" button on App Store. To my surprise, a couple of apps were updated before a display told me there isn't enough space. When I went to Settings>General to look at my storage, somehow I gained 30mb or so. This is what the trick does - forcing self-clean. Yes, iPhone DOES manage memory on its own by deleting unneeded cache/temp files. But this seems to be for ensuring iOS' optimal operation rather user space. In my case, taking pictures did not clear up those cache/temp files.
So I learned a trick. If my phone seems to be running out of space, I force app updates that are way bigger than free storage. This always gives me ~200mb of extra space. I once forced MS Word update (around 300mb) when free storage was less than 100mb, I gained enough storage to film an hour-long driving video.
For my trick, there had to be an app update with the appropriate size at the right time. But the video's trick can be done any time.
Also, I once looked at EACH one of ~3000 files from iPhone back-up (I posted about that experience on this forum a couple of times). There were many files from apps that had long been deleted, messaging apps' never-before-seen stickers, thumbnails from in-app stores, pictures I deleted long ago, attachments I downloaded AND deleted, etc. Yes, iOS does self-cleaning, but what were these files doing here? I wouldn't perfectly rely on iPhone to manage the storage.
