> It requires cryptographic randomness for each individual signature
This is false. Although the default algorithm does work that way, RFC6979 lets you do ECDSA entirely with pseudorandom numbers seeded by the message and key.
It's a little weird to refer to this as "false", since Pornin's RFC was published after EdDSA. Bernstein isn't writing an elaborate blog post about Bitcoin; he references Bitcoin as a way to provide context for readers who might not be familiar with actual protocols that use ECDSA.
The overwhelming majority of ECDSA applications do not use deterministic DSA; deterministic DSA is a novelty.
EdDSA uses something very similar to RFV6979, so the author had to have realized that just retroactively adding that small piece to ECDSA was a possibility. So I don't think it's really fair to call determinism an intrinsic property of either algorithm.
The overwhelming majority of ECDSA applications do not use deterministic DSA; deterministic DSA is a novelty.