IMO this is a poor decision, having a single point of exit for the flow means all the current is forced across that small cross-sectional area. So it’s cool that it will distribute across all the positive poles on the cells, and that’s definitely what you want, but you’re going to majorly restrict flow at that one point of exit. Most of us use another fold over to solder a length of exposed wire on, in order to keep that large distribution area going into the wire and not create a bottleneck.
You’re not new here, so I’m guessing you just missed it and/or didn’t search, but people have discussed and tried copper welding a few times. I’m not sure these are real results but the idea has at least been floated on occasion. Here with some external links as well. Testing. EV applications