I don't like when Claremont (or anyone else) does that.
The purpose was to make Illyana badass and on the edge of turning evil (a recurring concept in Claremont's stories since Dark Phoenix).
Still, Enchantress is an Asgardian witch on par with Doctor Strange.
She has thousands of years of experience with dark magic.
So, was it necessary ? was it even enjoyable to the reader back then ?
To Yana's credit, she did kick Belasco's buttocks, and he's had hundreds of years of magical experience.
Still, Yana's buttocks were kicked soundly when Amora wasn't busy with 6 other meddling mutant kids.