This speaks more to the complexity of web and web development than as a pro of spreadsheets.

You can create a super quick Python app with visualization and whatnot in about the same time as a spreadsheet. But then it's not online. And it's not best practice.

Web is just a fucking beast and then developers go in and add additional complexity.

It would probably be a much simpler web app if you made it just, like, a bunch of PHP scripts thrown in a folder. But they won't do that.