I presume the OP understands the risks.
Ironically some obligate corallivores can readily learn to eat alternate foods - I see it regularly with butterflys locally caught and shipped to my LFS. Will this work long term? IME with frozen DIY foods no. With pellets, doubtful.
But if someone is going to purchase with the intent to try a different method of feeding, you won't stop them. JMO.
I strongly believe if I can get them to eat spectrum pellets, they will survive. However, getting to eat is the most challenging. I assume they are similar in difficulty to the red sea larvatus.
In my experience, the tendency to eat is individualistic. Even in easy to keep types, some will eat, while others won't.
The problem isn't about getting the fish to eat. It's about providing a proper diet. Spectrum pellets have nothing that is natural to this butterfly's diet. The fish will eat it but won't survive on it...