People say this but I never saw it matter like you say. I know many ux/ui people in my network who I ask for feedback and help; I have never seen any difference in uptake from the vanilla theme version I did myself through to months of tweaking these guys did. Sure it looks tons nicer but it doesn’t reflect at all in (measured) user satisfaction, signups or usage. The default themes these days (shadcn etc) don’t make any of the mistakes you mentioned and users that are not obsessed with tech don’t really care ‘it looks like everything else’. Maybe it’s because I never do b2c and only b2b, but I never saw the difference, not in the last 30 years anyway. Even when these design systems and widgets etc didn’t exist, people didn’t care because there was nothing better; now there is ‘more than good enough by default’.

Design and branding matter a lot more than people realize. Not just in terms of appeal - it sets the stage for everything that follows.

Half the social media apps are the same thing: Feed, like, block people, follow, post (with image/video, etc.), hash tags, etc. but the slightest difference in design and branding sets forth a different content platform.

UI/UX isn't just aesthetics, it's utility and a huge part of what the thing is.

There are myriad of software that have been super popular despite having dodgy UI. But the whole point is not to care if your app is popular or not if the whole point is enjoying the process of building the app more than seeing it used by many.

that's the point of the article- that you shouldn't be worried about making things for something else if they're unlikely to care either way

with that said, I agree with your overall point, if you're determined to make something popular you shouldnt skimp on design