Note that the trucks are already allowed 2 tons extra road weight, so it's actually not unusual to have basically the same load capacity (within +-500kg). It does matter if you have a rotating crew driving express long haul, because then you don't have a mandatory 45 minutes of lunch break during which you can plug in to a 300~400 kW charger (and e.g. take a walk or visit a bathroom or actually have lunch) to get a shift limit of range out of such a "small" battery.
They probably took a battery truck with (in a worker-and-road-safety oriented market like Europe) excessively much no-recharge range to match their fuel cell setup. But you do that because it's fairly tame to add the marginal range of a full shift limit to a fuel cell truck; it's not economic to size a long haul battery to suffice without recharging for anywhere near the weight limit.
Green hydrogen is substantially more expensive than diesel per energy; and electric trucks can already beat diesel's in TCO depending on the kind of usage (e.g. notably express long haul is not competitive, but most highway single-driver operations are).
I'm no expert but a far stretch but if this most basic fact is already wrong then my trust in the remaining stuff diminishes. On top of that they is only relevant if all truck loads were limited by weight.
So, I believe that argument to be wrong in its entirety. And if we then factor in the CO2 costs, hydrogen is the clear loser in all regards.
A truck, including its load, must not weigh more than 40 tons. Let's take two comparable trucks: one with a battery, the other with a fuel cell. It turns out that the fuel cell truck's drive system is four tons lighter. This means its payload capacity is greater. Therefore, up to 20 percent fewer trucks are needed to transport the same goods. Instead of five trucks, there are only four on the road.
In the best case you can save acquisition costs, driver wages and insurance for one truck per every four others. It's going to take a while until you make that up with saved energy costs.