44 trucks in a month is not a particularly big wave, though I'll grant it's a sizeable step from previous sales.
Electric trucks do make sense for a lot of the last mile delivery sort of stuff (lowish and predictable max km per day, lots of stop/start, return to same base each day) so I expect this use case at least will become popular in the near future. As the article says though charging is a bit of a killer and will likely be more of a problem than the actual purchase price of the trucks. It'll be interesting to see if it leads to a shift towards the big companies buying rather than leasing more of their depots due to the capital input required for charging infrastructure (small companies are probably just out of luck).
You're allowed to keep it and you're allowed to try and use it to buy stuff but you won't have much luck doing so.
Turning up with foreign cash would be effectively the same as trying to buy stuff with precious metals, jewellery, or rare Pokemon cards - while there's value in the item it's not immediately verifiable, it doesn't fit with the usual workflow of the shop, and they're under no obligation to even consider this as a payment option.
You'd have more luck using foreign cash for person to person sales where bartering and swaps are more of an accepted payment option. Even then expect dubiousness and to lose a lot of the nominal value when it comes to purchasing power.