It's been a while since I used it but I did a limited trial of Hey and it was genuinely miserable to use. Not only did everything take a few ms extra, the entire interface was so incredibly janky and had no accessibility concerns at all. They were shipping their website to their mobile apps and it was horrid. I would not put Hey as a shining example anywhere for this philosophy

It's been a long time since I used Basecamp but that was decent enough