Laanx people don't look especially different, but they don't look like prominent Talad follower Joe. Only Joe looks like Joe. So, Joe disguises himself to look like prominent Laanx follower Larry. As long as he doesn't run into the real Larry or his close friends, he's golden (or maybe silver is more appropriate for Laanx...).
Also, if you stumble into the stripe clan and you have spots, a spell to change to stripes would definitely count as survival. Or if you're running from somebody, changing your appearance at all would work. They're busy looking for the guy with short hair, not Mr. Mullet. If you change actual facial features, the diguise is even better.
From
http://www.planeshift.it/guide/en/guide-magic.htmlits practitioners have a history of being the most innovative of any practitioners of the Ways of Magic
It's known that many disasters and epidemics were caused by the adepts of this ancient Way, that holds some spells with terrifying effects.
Wizards discovered that each glyph can create a spell effect and that many glyphs can be combined to obtain greater effects. To simplify casting of spells the glyphs are associated with a concept and wizards combine those concepts to form new spells.
Key words: innovative, epidemics, new spells. Talad didn't create the spells, but the glyphs. Whether he actually invented the glyphs is not specified, but if Vodul taught Laanx one, then Talad at least is not the sole inventor. But creating and inventing are different. We know he created the glyphs in Ylakium, unless unmentioned powers such as Laanx, Vodul, or the Black Flame also contributed. Regardless, the glyphs are sources of "spell effects" that can be combined.
The glyphs can't make just anything, but certain combinations, called spells, do exist. The recipe of the combination can be discovered and recorded, but the end result of the spell is an indirect result of the magic behind the glyphs, a possibility enabled by the magic's existance. So when Talad made the glyphs, he didn't get to make spells, just make the ingredients availible. He could limit which ingredients he gave his people, but it won't stop
all of the combinations. And some of the spells he may have wished them to use one way could be used another. For example, maybe he wanted them to start fires for cooking or warmth, but it is now used to fight. A shovel and a chainsaw are not intended to be weapons, but they make darn good ones when used in ways they weren't intended.
Say I go out and invent legos. I didn't invent the lego t-rex, but I enabled it to be created. If somebody doesn't provide you with all the pieces, you might not be able to create it. The legos are the glyphs. The plastic they're made of is the magic. But even the magic didn't create the lego t-rex. It's just another part.
So in short, what I'm saying is that Talad didn't actually create the spells, and his wish to help his people survive doesn't necessarily limit the types of spells available. Even if he didn't create enough glyphs to do it, there's no reason to believe that the current glyphs are the only ones, just reason to believe that most if not all
currently known glyphs come from Talad. Also, just because a spell doesn't make sense doesn't mean it couldn't be a possible combination.
I'm just arguing from a settings standpoint though, not a game standpoint. I haven't given much thought at all as to whether appearance changing spells should exist for use. If they did, I'd say make them temporary, like an "impersonate" spell, or a "turn me to an innocent statue" spell, like Mario's raccoon suite.