Yes, but then you can probe the pins and MITM, like you can with an external TPM chip. (See something like the TPM Genie) It's internal because it's more secure that way.
I read 'dedicated security chip' as something akin to an external chip like a TPM chip as opposed to dedicated transistors in the CPU die (which is more secure). So it sounds like we're agreeing.
Not sure if we are agreeing or not...