it appears these terminals have an aluminum ring over the head of stainless component, and is welded around the perimeter to cell terminal. The stainless has a head that is captured by the aluminum ring, rather than being threaded in like bolts/studs.
The stainless stud isn't the electrical path. Busbar or cable clamped to aluminum cap is.
Although contact area is smaller than when a bolt clamps busbar directly to cell terminal, I don't think that is any problem. It is OK for contact area to be much less than what would have ampacity for the current. Any heat generated in the (zero length) contact spreads to the terminals which are larger and is dissipated.
I think at the quite low 4 Nm torque specified for the threaded aluminum terminals, contact area is actually too large. It can't have enough pressure to make and keep good contact. More torque and more clamping force is more important than more area, compared to what that achieves. So the smaller area is probably an improvement. (For threaded cell terminals, maybe a 3-D busbar shape with smaller contact area or even specially textured surface to punch through oxide would be better.)
The actual contact area for bolted connections is quite low, many small contact points with the rest of the surface not quite touching. In the case of aluminum, points breaking through oxide. The weld bead is relatively narrow but provides more cross section. Unfortunately you still have clamped contact to aluminum (I think) with the welded-on studs. Would be better if the contact surface was plated, e.g. with tin.
Best solution would probably be welded busbars between cells, and welded terminals on the end cells, with larger/stronger threaded terminals to connect cables. Next to that, I would go for these welded on threaded terminals for every cell.
Make sure your cables don't experience force that causes them to rotate in the bolted connection.