Biscoff is a registered trademark of Lotus Bakeries, while speculoos is a generic name. Hence why Lotus markets its under its owned name, and not the generic name; especially outside Belgium/Netherlands where people don't know about speculoos.
But to be honest, as a Belgian living abroad, I'm just happy I can find it at all lol. Was surprised to even find the 'crunchy' spread in my local supermarket.
As a Belgian living abroad I'm waiting for the day prepare/filet americain, proper mayonaise and "broodjes" are available world wide. If people knew about it, it would be as big as sushi!