I'm quite fond of the poncho/tarp combo, depending on conditions, but even if bad (wet) weather is anticipated I'm very likely to bring my poncho, and it's the Golite poncho that I use. I like the fact that it's an extended length poncho sized well for covering a pack, but the lower back snaps up to shorten it to use without the pack in camp.

I thru-hiked the PCT this year, and actually carried a smaller poncho tarp as my only shelter and raingear for the first 700 miles, as rain is typically not a problem in SoCal, and I wasn't disappointed. I actually set it up as a shelter once in that stretch and got a few drops on it. I also carried a very light (not waterproof) bivy, which I also used just a scant number of times, a couple when I was concerned about dew fall near creeks, and once when to keep bugs off my face.

In the Sierras I switched to a light rain jacket and tarptent, and those worked well enough, but a poncho would have been fine there too I think, at least for rain shelter, and at least this year, for both, except for bug protection perhaps.

At some point (I forget when) I switched my light rain jacket for a (golite) poncho, though I kept the tarptent. I just like a poncho better. When the weather isn't too cold there's nothing better IMO than wearing a poncho and shorts. I don't have much trouble with wind, as I use some shock cord or just regular cord to tie around my waist outside the poncho. For me and I think for many, it's the ideal balance between rain & wind protection and yet being able to breathe well. Too often in a full-on rain jacket I get as wet from sweat inside as from rain outside.

The golite poncho is not a roomy shelter. I wouldn't enjoy camping under it for an extended rainy period, but it certainly could be done. And per above, you get no bug protection. Some people are happy to defeat bugs with just a headnet, others might use a "bug bivy", I think both six moon designs and mountain laurel designs sell a version of this.

In terms of ways to set it up as a shelter, the golite poncho can be used pretty much the way other tarps can, though (for better or worse) it doesn't have the catenary curve, and of course there's a limited set of tie-outs, and in at least some configurations it works best when you can pull the hood up via an overhead (typically over-a-branch) cord. But you can make a pup tent, or a lean to, or something part way in between, or other structures, based on your experience and estimate of where prevailing weather will come from. I also used the golite poncho for a hammock shelter (hennesy hammock), but found it a bit on the scant side --- it seemed like I could never get really reliable complete coverage, though it was pretty close --- I did spend a few wet nights with this configuration last year with no ill effects, but I would indeed want something a little wider and possibly even a touch longer to give really complete coverage.