It's not a terrible idea, but it might be overkill on the CT125. A lot of the delicate parts sit "inside" the contact points with the ground (the plastic panels, for example, and my delicate snowflake butt).
In terms of crash n bash protection, of the ADV/trail bashing trips to hug the ground by CT125 riders on Youtube, several have pranged their headlight cover which apparently is a bit prone to damage. The video I know for sure, only because it happens in the first 2 minutes of the video, is Ang doing that in the
Hurricane Creek Rd. video. Separately I saw someone else (can't remember who) break their headlight mount in exactly the same place. A third video had the cover fall off Kirki tanker style and it needed to be electrical taped back on until a proper fix could be made. That one I can imagine as being quite the inconvenience, so if you had to invest in some protection, around the headlight is the one I'd recommend, as well as the ol' tape and zip ties in the kit. I'd recommend electrical over duct tape in this case unless you live somewhere hot as it's easier to remove and you don't need a ton of strength to keep the cover on. Plus duct tape goo can be a pain to get off later.
EDIT: the other protection that has actually been used by CT125 riders, again also Ang aka
@SomeGuyRides, is the bash plate is a bit soft. This is pretty standard for any moto that ships with a stock bash plate, looks good, works ok, but could definitely be improved on.