My understanding is the onion service was launched to provide access for people in places where Twitter is blocked. How is this "irrelevant to the business"?
I'm not someone who's ever used the onion service, but as someone who accesses the site regularly over VPN, I can testify that it's a huge PITA. Tons of very aggressive captcha-type challenges (various tasks, never simple text recognition, but not Google ReCaptcha), often 5, 7, or 10 to be allowed to proceed.
