For one, you might not have much to chat about with your baby, so doing baby talk might actually get in more language training.

In a good environment babies should be exposed to plenty of language. There's tribal societies which don't talk to their kids until they start to talk themselves and those kids turn out fine by all metrics researchers could throw at them. What they do do is take them with them everywhere.

You do not need to capture a baby's attention for them to sponge up information. They do pretty much nothing else no matter what you do.

What has been shown to be beneficial is to give them the opportunity to talk to their caregivers earlier, figures that language capability develops faster than the capability to make complex sounds, it's the whole point behind baby sign: So they can tell you that no they aren't hungry they want their teddy. Doesn't benefit language skills, it does reduce frustration (you might figure), bonds to their caregiver, and benefits both party's emotional states.