I can't imagine why anybody would consider this controversial in the least. Id we are living in an attention economy where anybody is allowed to make a small debit from your account at will. Giving people more tools to manage those debits should be lauded.
Kinda like a website that is limited to 160 characters. Never fell in love with Twitter and looking at the top trends I often feel like wasting time on that platform.
But I agree that Twitter is basically an attention distributor. I get the impression that Twitter focuses its ambition to pander to self-expression and many topics that could have been interesting degrade to something that feels even worse than cheap PR.
Sadly, however that happened, Twitter became a platform to advertise political positions. That is probably why so many people see such features with mixed feelings.
I disagree that people make debits by replying, even if it is done in bad faith. If you put something out there, you are likely doing that yourself and nobody takes anything away. By hiding something you take something away from readers.
What would you think of spam? Isn't that clearly an attention debit? I would say that all replies, wanted and unwanted, take at least a small amount of attention. And if the fraction of useful to not useful replies decreases, that's the SNR going to crap.