So design is not purely about function, for that is engineering. Design is not purely about aesthetics, for that is Art.
Design, as I understand it, is to produce pleasing interactions with a function that empowers you to achieve what ever task is at hand.
In the example cited by the OP, and by you, there is a clear and obvious difference between the two.
Let's start with a simple cross compare
Brief: I, as a user, wish to visit the home page to understand what it is.
Stripe's page manages that in about a second. The visual hierarchy makes the two core messages stand out and directs my eye to them. "the new standards in payments" and "the complete toolkit for internet business" - should those messages trigger a need, a job to be done, a want, an urge then it very effectively functions.
As I scroll through, the messaging is clear, the design is delightfully simple, but with lovely, unnecessary touches, that communicate quality, care, craft and respect towards the customer.
Sourcehut however draws my eye to announcing the source hut project hub, but i'm not yet sure what sourcehut even is. I scroll a little more. I read a lot of words I understand as a developer, but the answer of "what is it?" elludes me. I scroll back to the opening paragraph "Welcome to sourcehut! This suite of open source tools is the software development platform you've been waiting for. We've taken the wisdom of the most successful open-source communities and turned it into a platform of efficient engineering tools." Okay, so jargon word soup aside, and given that both sites are engineer focused, why is this so hard to parse? What tools do i want? Or not know I want?
I see website that has been made simply, quickly, and for one purpose, which seems to be to exist as a page for those who know and understand what it is, already, to live somewhere. It does not communicate care, craft, ease of use, and it seems to look like the sort of sites we downloaded printer drivers from back in the day.
The purpose of beautiful sites, software, apps, whatever, is to celebrate the world, to create something wonderful, to be empathetic to our users, our fellow humans, to make something that makes us smile, that delights for no reason than it can.
This is not an experiential bias, it is a core element of society, that aesthetics matter to many for a multitude of reasons, and perhaps, it is a bias that you have that chooses to reject it, for reasons I can only hope are not rooted in rejecting it's purpose within humanity because "it doesn't make sense to you".