If it's the case that there's almost never the need to reach for it, and I do find myself in that camp, then a harder question is begged, why is it so popular?

I think there's a lot of technologies that are in the category of categoric mistakes to use, but popular enough and inert enough that they don't get dropped. There might be lots of different explanations depending on the technology, a lot have a reason the moment they are released.

Many third party tech becomes de facto standard at some era, then those features get incorporated into more mainstream tooling like browser css, and at that point the third party tooling exists only because of inertia and adds little value, but increasing supply chain and complexity risk.

Another example on this category is Axios which was essentially a cleaner DX for XMLHTTPRequests in client side javascript before Fetch, and later a polyfill for it. Nowadays it's a blunder to include it, but it ended up in stackoverflow answers and training sets, so it's "safe" to include. Developers that are on the bleeding edge drop it, but those that are catching up and reading tutorials or classes from the previous era, or using llms, use the previous era cutting edge technique, because they aren't evaluating all the parameters of a choice, they are just going with whatever someone else is using, which causes a coalescing around certain central technologies like React, Kafka, Redis.

Regarding Redis, my understanding is that it was popular during one era where databases were used to store state because we didn't know any better and people were moving fast and breaking things, so it was developed as a sort of hack to move things from a database into memory. But nowadays people just use it wherever (because it really is the most blank microservice you can think of, you can slap it anywhere), and people implement it off the bat.

There's lots of more specific reasons why bad third party deps persist. In python there's a library called python-dotenv, which is a categorical mistake to include, but people do it because they come from Node where it is a standard practice. But there's the standard nuance that in Node, it is a built in, but in python it is a third party dependency from a random dev (no offense to the dep dev, only to the users of the dep). It literally is replaceable by calling Open(), write(), and close(), but there it is with a lot of downloads waiting for the day it is targetted and hacked to capture millions of .env files. Personally to me it would be strike 1 of 2 if someone imports it, but there you go.

Yes, there's no reason to import tailwind, it adds nothing, the idea of:

red-color { color: red}

big-text { font-size: 14px}

Is as laughably low quality, the application of a technique in form but not substance, similar to Getters and setters in Java, effectively making every property of a class public, but formally implementing the private keyword and access through functions. 100% a categoric mistake to implement.

I've written elsewhere of a phenomenon where devs avoid lerning a base technology, and rather end up learning a tech on a higher abstraction that ends up being a 1-for-1 of the lower tech, but it gave them the hope that they could avoid doing that learning, and they only drop into that realization by piecemeal ala "we did it not because it was easy, but because we thought it would be easy", and the only cost is that they learned the non-portable version of that technology and now they are vendor-locked professionally into that technology so they will spread it to the next repo, company, job posting and so on.

There's analogues in biology of inert viruses or parasites that don't materially cause damages, but their lifecycle depends on the host. Although to some extent, by competing for resources they always cause SOME damage, but it is important to notice that not all viruses or damages are highly damaging, that's a rare situation of very extreme pathogens, it isn't very beneficial to kill or damage your host. In fact many may be commensal, but there is a tendency to harm.

In conclusion, I think tailwind and such pre-ai slop-deps are more popular because they are inert viral parasites rather than because they provide value.