People still buy desktops??? Serious question. I still use one, but I'm old, and using one I built more then 10 years ago and it's still works great. Only thinking about getting a dual monitor card because I have too many monitors around that I'm not using.
I bought a new-to-me(second hand, but not old) desktop last year and I still use it regularly. Mine was a 2019 iMac 5K.
If you mean desktops as opposed to laptops-yes I use a laptop regularly(that's what I'm typing this from) but there are advantages to desktop format computers:
1. Ability to use the input devices of your choice. I have a mechanical keyboard, the much-maligned(but I like it) Apple mouse, and a graphics tablet(used for zoom meetings/video lectures).
2. Larger/higher resolution displays, and usually the ability to use more than one
3. Able to semi-permanently connected stationary peripherals like large external hard drives, etc
All of the above can be done with a laptop and a docking station, and I've gone that route in the past but desktops still have their advantages:
1. Desktops generally are physically larger, which actually has real world advantages for performance. For many applications, there are "laptop grade" and "desktop grade" components. Laptop components often are designed with an eye toward size and efficiency, while desktop components tend to have fewer constraints on power in particular. Even where desktops use laptop components(and Apple has really blurred the line on those with the ARM based Macs) the larger desktop cases allow bigger heatsinks and generally better airflow. That allows better sustained performance as the computer can move heat out a lot more efficiently and doesn't have to throttle(reduce performance) to manage it. Even at roughly the same level of performance, a desktop will generally do it much quieter and feel much less "strained."
2. Again, this is a moot point with ARM Macs since memory isn't expandable, but most desktops allow for more memory expansion than their laptop equivalents. It's pretty unusual to find a laptop with more than two memory slots, where many desktops will either use full size RAM DIMMs(which generally are available in larger capacities than the equivalent laptop sized ones), or if a desktop does use laptop-sized SO-DIMMs, like my iMac, it will often accept 4 of them.
3. I only barely use my Mac Pro tower anymore, but PCIe expansion slots can be a big deal to some people. The current model Mac Pro is actually kind of a joke to me as it's basically a Mac Studio with a PCIe bridge, but still the slots are there for people who need them(just as long as one of those things isn't a graphics card...). Thanks to ports like Thunderbolt, you can now attach PCIe cards to your laptop, but that's an expensive and less than perfect solution depending on exactly what you need to do.
4. In general, desktops have more ports. This is less important now with things like fast USB with lots of bandwidth for hubs as well as more general purpose ports like USB-C and Thunderbolt, but still it's nice to just have the ports there.
5. I'm not a gamer, but many people who do game want to be able to stuff the biggest, baddest, hottest graphics card they can into their computer. You can use things like eGPU boxes(external GPU) to get this with laptops, and in fact I use an eGPU with my iMac, but there are some limits to just how much performance this can offer. There are plenty of other applications that like a good GPU. I do a lot of photo work, and Adobe has gotten better about leveraging the GPU where appropriate in Photoshop and Lightroom. As an example, in the last couple of months Lightroom has added a superb "denoise" function that benefits from GPU power. This is an extreme example, but I timed it on a 40mp RAW file on my 2015 MacBook Pro and it took about 12 minutes to run. I connected a Radeon RX580 in an eGPU box(not officially supported on this computer, but can be made to work) and the same operation took a little under a minute. My iMac is even faster with the same GPU connected, but a better card installed in a 16x PCIe slot in the computer would make an even bigger difference
To revisit my laptop+docking station comment above, too, if you're buying a laptop to primarily use at a desk and will use a monitor, keyboard, and mouse, why waste the money buying them both separately and integrated into the computer?