...Nanopaste is a 24 hr one time use only at a minimum of 500
. Many components of a traditional disguise kit, even given the same base cost, would be reusable and as pointed out by hobgoblin, wouldn't necessarily expire after 24hrs use. Nanopaste, particularly the large size container (Availability 16), is also difficult to come by. You just don't go down to Bill's theatrical shop & buy a case of it.
Keep in mind, Corp security & Law Enforcement are well aware of Nanopaste and nothing would stop them from developing countermeasures to compromise or detect its use if they are at all suspicious (as I would expect them to be).
I agree that being able to "act" the part is as, if not more, important as the quality of disguise itself. A true covert disguise artist would need a good Con skill (Acting) as well as Artisan (costuming) and supportive knowledge.
Disguise skill is not limited to impersonation, but also can be used as a cover to keep the heat off or simply for anonymity during extended missions. Here is where more conventional forms of disguise would be better (even over spells). 1 week or more at 500 - 1,000
per day can get a tad bit expensive and then there is finding enough paste to make it through the duration.
I see traditional disguise methods still being fairly common, and Nanopaste as more the exception based more on its availability rather than cost.