[namibj]

Bandwidth is far more power hungry for DDR, but capacity is far cheaper.

If the bandwidth capability of DDR suffices, HBM isn't worth it.

At least with LPDDR's; GDDRs may well not be worth it under data center TCO considerations due to the high interface power usage. Feel free to correct me if I'm mistaken, the numbers in question aren't too easy to search for so I didn't confirm this (LPDDR vs. GDDR) part.