> At best, SMT yields a ~10% to 20% throughput boost over a single thread.

Exactly, which is a significant benefit for how marginal the costs are.

> It's not the same thing. Bulldozer arch sits between a true 8-core and 4-core + SMT implementation.

Then surely it should be even better than 4 cores with SMT?

If you're going to argue that the problem with Bulldozer was it's weird semi-SMT solution, you need to explain how it would've been better without it (aka as a regular quad core). Because even if it just gets the 10-20% performance improvements from being a form of SMT it would be better to have it than to not. And if you have lots of integer unit-bound threads, it should be even better than that.