Background/problem situation: I have an M1 MacBook Air. The M1 chipset supports two displays. So on an M1 Mac Mini, you can have two external displays. However, on a MacBook Air, which has the same chipset as the M1 Mac Mini, one of the buses or whatever for displays is taken up by the built-in monitor. There appears to be no way to reassign that, even in clamshell mode. So the maximum number of external monitors the MacBook Air can support is 1 external monitor. So if you want to support more than 1 external monitor, you need some sort of workaround like DisplayLink.
Potential solution: DisplayLink names both hardware in certain USB docks and the software drivers that support that hardware, and what they let you do is run more external monitors than you otherwise could. There are other solutions that let you do this for Intel Macs - like display outs in TBolt docks - but my understanding is that their isn’t drivers support for Apple Silicon machines. I have an Apple Silicon machine, so Intel-Mac-only solutions won’t work for me. I think there might be expensive commercial solutions that would work on Apple Silicon machines. AFAIK, DisplayLink is the only affordable, consumer-oriented solution for supporting additional external displays beyond what the system allows that works on Apple Silicon.
Additional details: The number of external displays you can support through DisplayLink is determined by the number supported by your DisplayLink device. These are separate from the number of devices supported natively and don’t count against that total. So, for example, suppose that you have an M1 MacBook Air that supports 1 external display, and you do what I’m considering, which is buying a USB Hub with DisplayLink support that supports two monitors through DisplayLink. The total number of external monitors that you can support is 1 external natively + 2 externals through DisplayLink = 3 external monitors total (which is the number I’d like to use). And on a Mac Mini, because you don’t have the built in display using up a slot, you could support 4 external monitors (2 natively + 2 through DisplayLink).
The MacBook Air only has two USB-C slots, so if you want to have such a 3 monitor setup, I think it makes sense to have a DisplayLink hub, since you’re not going to have any additional free slots to dedicate to power delivery and whatnot. So having one DisplayLink-capable hub that can support power delivery, ethernet, USB connections and so on, makes the most sense to me.
Because of how it works (it’s not an external GPU but closer to an adapter), DisplayLink puts additional load on the system. I have read that this is not really noticeable for ordinary use with a relatively ordinary setup (e.g. 1-2 monitors), though some people do stuff like 6 monitors which seems like it might cause a problem.