Indeed, HDDs are made to be fixed firmly. The inertia brought on by the disk heads' movement must be overcome by the bulk of the entire computer or the enclosure. Because of this, employing rubber mounts to eliminate HDD vibrations in contemporary PC cases is actually detrimental to the drives.
The point about rubber mounts fighting the drive's own inertia makes sense, though it's a bit removed from the PineBook Pro topic. Since the machine ships with solid-state storage, that whole vibration concern doesn't really apply to it, which is one reason it holds up better for editing than people expect. I'd be more curious how the eMMC and SD card handle sustained write loads during a timeline render, since that's where a budget ARM laptop usually shows its limits rather than in spinning-platter mechanics.
The eMMC/SD write-load question is the practical one for this machine. Sustained scrubbing and render cache are where slower flash and the SD bus tend to show up as stalls, not the lack of spinning platters. If the PineBook Pro is holding up for editing, it would be useful to know whether the timeline and cache live on eMMC or the card, since the card interface is usually the tighter constraint.
The storage question is the one I'd want answered too before trying this — I've edited short clips on far weaker hardware and the render cache location made more difference than the CPU did. I keep my project files on a decent SD card and the cache on the internal drive where I can, and it keeps the stuttering down. Encouraging to hear it's workable at all on this machine.