At the very least it demonstrates that in handheld play, graphical reductions can have a positive impact on making the gameplay work on a smaller screen - something that would be crucial for Nintendo's hardware.
However, Digital Foundry also point out that the mobile version of PUBG has to run across a wide range of potential hardware configurations, while a Switch port would benefit from a fixed target platform - something which could lead to a superior port, albeit one that would require some additional work: In terms of setting a graphical threshold for what a potential Switch version could deliver, this port probably isn't the best evidence.
Although Nintendo's console is indeed based on a mobile chipset that has hosted the same OS, the conversion tested here has to run on an extraordinary diverse range of lower power devices, using an OS and graphics API that is notorious for under-delivering on the core hardware's potential.
While aspects of the work here may prove helpful in helping to address problematic aspects such as the CPU question, Switch developers would have the advantages of targeting a fixed platform with a superb 'to the metal' development environment that has now proven itself many times over.
Of course, all of this is pure speculation but we already know that PUBG Corporation is mulling over its options for when Microsoft's console exclusivity period ends, and with Switch being such a hot ticket right now, it would be the perfect platform to port PUBG to.