It could eventually be the case that providing the full speedpaint for a given digital artwork significantly bolsters credibility in the minds of audiences who universally reject AI-generated content as cheap, spiritually enfeebling, and provided largely for commercial motivation. Such a thing can serve as an informal certificate for an art's "human-ness". This approach wouldn't necessarily serve as strict validation that something was not produced by AI, but it would serve as additional evidence that the creative work in question had demanded frequent or exclusive human involvement.
Ironically that would be useful data for AI labs to take. It could be used productively to make digital art training material or nefariously to make models to displace those artists.