And there's nothing wrong with that. But people got really pissy and Upset about the Veronica module and we have no idea what is going on with it. Just seemed excessive.
Anyway...
It's not really big, but to achieve that float feature it has to have a fair amount of magnets which add a decent amount of weight. And if that weight bumped the overall package over a certain amount it would possibly add a lot to shipping charges. And the extra arm appears to contain electronics which can include a fair bit of weight too.
And given they put the HB up for sale without any promise of more to come and people bought it. And they set the production numbers and expectations based on those PO numbers I can see why they wouldn't throw more stuff in and get no additional money for it. Doesn't mean they won't, but there's no real incentive to do so.