Unsurprisingly, laptops make bad to terrible desktops
In response to my entry on the security problem for public clients, Jeff Kaufman suggested laptops as an option on the grounds that they already integrate everything into one physical unit. Unfortunately, I don't think this is workable. The core problem is that laptops make terrible desktops, especially in a setting with relatively untrusted access to them. This shouldn't surprise anyone, since laptops aren't designed to be desktops.
A typical university desktop is cheap, has a relatively large screen (17" is the minimum entry point these days and it often goes larger), is turned on essentially all the time, and must be physically secured in place. It should not have any easily detached fiddly bits that can be removed and lost, because sooner or later they will be. Ideally it should be possible to set it up in a relatively ergonomic way. Some desktops need more than basic computing power; for example, the desktops of a computing lab are often reasonably capable (because the practical alternative is buying a few very capable servers and those are often really expensive). Partly because of this it's an advantage if things are at least somewhat modular.
None of these are attributes of laptops, especially in combination (for example, there are cheap laptops but they're cheap partly because they have really small screens). Your typical relatively inexpensive laptop is relatively slow, has a small screen, has historically often not been designed to run anywhere near all the time, is entirely non-modular, has external fiddly bits like power adapters, is not really particularly ergonomic, and is often hard to secure to a table. None of this is surprising because this is all part of the laptop tradeoff; you're getting convenient, lightweight portability for periodic roaming use and giving up a bunch of other stuff for it. You can use a laptop as a desktop and many people do, but it doesn't make laptops ideal for it.
(One sign that laptops are nowhere near ideal desktops is all of the aftermarket products designed to make them work better at that job, starting with laptop stands.)
If you don't care very much about offering a decently good environment, this is actually okay. A bunch of cheap laptops with cable locks in an attended environment suffice to let people do quick things like check their email on the fly, and they might be overall cheaper than custom sourced kiosk machines in enclosures with decent sized screens and so on. And this setup certainly encourages people not to linger. But if you want to offer an attractive environment I don't think that doing this with laptops is viable, especially if you have to worry about people walking off with them. At least for university provided public clients, I think it's desktops or bust.
(Whether or not universities should still try to offer client computing to people is another can of worms entirely that calls for another entry.)
(I'm not exposed enough to modern laptops to know how happy they are about being on and running for hours and hours on end. My relatively old laptop spins up its fans if left sitting powered on for very long and I'm not certain I'd want to let it sit that way for days or weeks on end; if nothing else that might burn out the fans in much shorter order. And they're not exactly really quiet.)