MichaelS has his own opinions about things. I'm not saying he's wrong, but his opinions are shared by a minority of bonsai practioners.
It was the "invention" of wiring that really made bonsai an art. In fact, I know of no other horticultural practice that uses it.
You can use "clip and grow" to a certain extent. The Chinese perhaps use it more than the Japanese. But a tree styled exclusively with clip and grow tends to be more angular. Wire allows the artist to put in subtle curves.
Wire is a tool. Just like pruning shears and concave cutters.
Wire, when it's done right, is hardly noticeable.
There is a myth that trees when shown, should be shown without wire. Like everything with bonsai, "it depends". Generally, conifers can be shown with wire. The green foliage hides most of it. I have heard some judges say they will accept copper wire on a conifer, but not aluminum. Aluminum is more obvious. Also, trees should not be shown if the trunks have wire. Even if the wire isn't bending the trunk itself, just acting as an anchor. So, to wire a tree for show, the artist needs to figure out ways to run the wire across the back of the trunk rather than the front. That is acceptable.
Generally, deciduous trees are shown without wire. The big shows in Japan are during the winter, and deciduous trees are appreciated for their branch structure. Since they're bare when shown, wire would be too obvious.
Ha ha! I love throwing the cat amongst the pigeons.
So let me start by saying, I wire everything. All my cuttings and seedlings (and I grow hundreds of them) get wired for trunk movement. Why? It saves time. I use wire to position deciduous branches but do not use it to shape them. Cutting is unquestionably the best way for that. (if you want a natural look). Forming conifer branches by clip and grow is very difficult and probably would take 5 times longer than using wire...so I use wire.
It should be remembered that tree branches in nature are not shaped by wiring BUT they are shaped by clip and grow. (amongst other things like shading, wind, weight etc. of course) Whether by chewing insects or violent storms, branches/twigs are broken off or killed in some way and the next one takes over. This leaves an angular transition and that's why cutting looks more natural obviously...
Unfortunately wiring becomes a bit of a cop out after a while. It takes much more thought when cutting a branch than when wiring, and because we tend to look at other bonsai for inspiration (which have also been wired) and the end result is often very artificial. A good example of this is the wiring of a branch into a flat fan shape with all branches on the one plane as everyone does on most pines and junipers. Natural branches almost never grow this way. Maybe, perhaps! on Cedrus species and some other conifers here and there. The end result. Lots and lots of cloned trees which all look the same (because they were all trained the same)
Wiring is not indispensable but it is very helpful. We just need to start thinking a bit more on the application. (actually I'm doing a talk on this very subject next year...wish me luck)
The horticultural aspect must always be considered as well of course and one of the reasons for wiring into a fan shape is to allow for light penetration to all areas, but there are other ways.
Some things simply must be wired and Junipers are one of them. Another example that I'm working on is an Australian coastal tea tree which can have shapes as convoluted as any juniper so they must be wired all the way as well.
So I do believe wire is a great tool but I think it is often done badly, mindlessly and sometimes unnecessarily.
@Eric Group, You will notice in my first post I did not once mention that we should not wire or that you can easily do good work without wire. So I guess I don't need to show you an only clip and grow tree. I wouldn't even know were to start. I might have one or two, I'll need to look..........