Watched the video. So it's not the bulb that needs soldering, that's just the two balancing wires. This could have been avoided with a different design and that would have made the bulb more easily user-serviceable. Although that nameplate sticker adhesive would probably be in a bad shape pretty quickly (but if you replace it once or twice during the vape lifetime, should be good enough)
I imagine the second wire is there for redundancy but technically a single tap between the two cells is enough for balancing. Both ends of the chain are available at the bottom terminals. Electrically all the top, including screw caps and the 4 pillars are I believe at the same potential, unless I missed something.
Due to tolerances the pillar ends need to be manually aligned to fit, so it's probably tricky. And of course with the benefit of hindsight everything looks much simpler. But I believe there could have been a way to make a friction contact (like battery tabs in your average cell holder, or some other form of spring loaded contact) from the side of one pillar directly to the PCB, eliminating the need for the tap wire.
But overall it's well thought out. We knew that from the manufacturer provided schematics already. And even with that detail, anyone with average soldering skills should be able to service it (although you probably need a good iron with plenty of power to overcome the thermal mass of the pillar plus the high temperature required for lead-free to flow)