We're really talking about two separate things here, in some cases. Some projectors can take a flash drive through their USB port, and present from it. In normal cases, that means the projector has at least a basic image player, and can make a presentation out of a series of JPG images. There's nothing new about that, and Powerpoint, for example can be outputted as JPG images for such a purpose.
The other aspect is DisplayLink and the ability to interface with a computer via USB instead of standard VGA type inputs. DisplayLink was already covered above.
Several projectors reviewed have a laser pointer on the remote. It should be considered whether students will be running the projector from the remote, and therefore if there should be concerns about those laser pointers. Out here in California, (not school related) there's even proposed legislation, to limit or ban the sale of laser pointers.
Years ago, I'd say a lot most projector remotes did have lasers. Why the dramatic decrease (especially since the costs have dropped a lot)? Easy, Students! Putting a laser pointer in the hands of a student may open up all kinds of potential liability issues. I don't know whether a school needs to really worry about it, but it's apparently convinced several major players to remove laser pointers from their remotes in recent years. The vast majority of projectors mentioned in this report, do not have laser pointers on board. I'm probably over-reacting, but wanted you to be aware of a potential liability. I certainly would not recommend eliminating any projector because it has a laser on the remote. At the very worst, cover the lens with some tape or marker, or anything that blocks the laser, if you are concerned.
Pointers are a whole different story. Epson, for example favors a pointer over using a laser. With their pointer, you can put up any of several styles of pointers (arrows, a "laser dot", fingers pointing.) You move them around using the remote's navigaton. That's not as fast as a laser pointer, of course, but it gets the job done with no liability issue. This year most non-interactive projectors had neither laser nor pointer, but at least 4 or 5 did.
Of course all interactive projectors are at the minimum pointing systems.
We are not networking people here, and don't dare evaluate performance. But we can comment on the general usage. One purpose is command and control - that the projector can be remotely operated,by the teacher (via computer), or, be shut off, automatically at 5pm every Friday from a remote server at district office or by the school's IT manager.
From Projector to Network: Many networking projectors offer email notification through the network. That means the projector can email an adminstrator (or several) if a lamp blows, a filter needs changing, or to report a malfunction (assuming the problem doesn't affect the networking).
Adding projectors to your network, can, per the examples above, save money. Leaving a projector on all weekend will use a couple bucks of electricity, and waste lamp life. Email notifications can help with management and efficiency, and probably improve uptime slightly. Remember, some projectors will shut down when lamps reach their full life. An early reminder can prevent a panic, and down time.
More and more projectors support protocols such as Crestron's RoomView which can allow messages to be pushed out over the network and displayed on the projectors all over the school, or district. That same network person could power up all the projectors and send out special announcements, etc. Very handy in emergency circumstances.
No doubt there are schools using wireless networking for handling presentations, but it is certainly is relatively scarce in the classroom, compared to say wired networking. It can certainly be a convenience, allowing a teacher to move their computer around the room while still using the projector to teach. In a properly controlled environment, perhaps a computer lab, wireless offers some interesting abilities. As an example, Panasonic had a projector that could support either 16 or 32 wireless computers, allowing switching between them, so that an instructor could have any one student's computer screen routed through the projector.
Wireless networking is definitely favored more when laptops rather than desktop computers are around, at least in the US.
That's worthy of some thought, one thing I've learned, is that we have a huge amount of old wiring in the US. Many countries, newer to technology than we are, in many cases, are reducing infrastructure costs by skipping the wire, and going wireless. In many countries now, cell phones rule, there aren't land lines. Are we too focused on using wire? Can wireless reduce costs? Not my call. You'd have to figure that out for your location.