It's freaking heavy at 2t. It's not that small or aerodynamic. It's battery pack is definitely behind leaders in net capacity.
What makes it run that long is that they don't overprovision the battery that much, so much more of those 60kwh is available for driving.
In addition to that, BYD uses PM BLDC motors that are better than induction motors at doing regen at low and very low speeds, which is much more important for city driving.
Add to this that their battery and electronics can take more regen current, and do it more efficiently.
there's a reason they overprovision. the battery is going to wear out way sooner than their competitors.
The biggest downside is its lower specific energy, but it is compensated by all of things above, so the net capacity and energy density comes close to other chemistries. However, working around all of those "sharp corners" requires a very different engineering approach from mainstream EVs. So that's a second point. Competitors largely don't bother going deep with engineering.
The engineering philosophy there is much closer to their electric busses. Much more manufacturing conscious, with a lot considerations for commercial use.
They think of heavy users who will use the battery for 2k+ cycles with minimal service, and go through multiple battery packs through the life of a vehicle.
So with all that said, I wonder if they are on to a good idea. There is so little maintenance on these EVs that the occasional battery swap might be fine, cost-wise. You could even sell it upfront in installments -- new battery after x years.