Buildzoid is great, but worth noting he has a very specific perspective which is that of a hardcore enthusiast (hence the name of the channel), and he often points that out, but here I think he ends up kinda just saying "why not just stick with the old ones", which is fine in comparison to something that sucks, but it doesn't hold up more generally for most people.
I get he may not care, but plugging four individual power cables into a GPU is a pain for consumers, and having a single connector for everything is great from the normal consumer perspective.
He eventually gives a good reason for it. The old cables have a safety factor of something close to 100%, where as the current connector has a margin of 15% or so. (Going by memory here).
The takeaway being, even with a small fault in the connector, there's more than enough margin to ensure safe delivery and therefor, no molten pins or terminals.
The current connector seems to lack this, and if one of the terminals does not make a solid connection, then the drop in effectiveness is enough to push it out of spec and cause a failure.
I do greatly enjoy Buildzoid, and I was eagerly awaiting his video (and one from Gamers Nexus; note they haven't commented yet) from someone who actually looked at this from an EE perspective. I recognize his video was titled "rambling", but he largely repeated himself for 30 minutes, and scattered the relevant datapoints in the video in a few short snippets. A little planning on his delivery would gave gone a long way.
I get that, but if we can provide a safe single cable option, it's clearly preferable for a number of reasons. I don't believe this converter being badly made means the whole spec is not viable.
How often do consumers plug power connectors into a GPU for that to be a problem? Spending a few minutes routing multiple power cables for an expansion card that once installed sits in place for years doesn't seem like a big deal to me.
Clearly it's not a huge deal, but it's still preferable. Not having to route for SATA drives thanks to the rise of M.2 is often praised by people who build PCs, and it's a similar kind of deal. A new spec that is more convenient is still a selling point vs the old spec on new PSUs.
The dongle is a short-term conversion because people have old PSUs. In the long term this standard will be built into modern PSUs and it becomes a single cable.
I get he may not care, but plugging four individual power cables into a GPU is a pain for consumers, and having a single connector for everything is great from the normal consumer perspective.