The charging infrastructure is one of the biggest advantages their core product has.
All Tesla owners can take advantage of the higher speeds, relatively low charging price (at least in my area), and plug and charge functionality and that goes a long way in closing the sale for first time EV buyers.
So although not a core product itself, it’s one of the biggest selling points they have. Even non-teslas can charge at compatible stations and that’s just more profit for them. Combined with NACS being the new standard it makes sense to keep investing.
This decision doesn’t really make sense. You’re right though, we’ll see what happens ¯_(ツ)_/¯