You choose the affected creatures

The feature is not indiscriminate. It applies to creatures of your choice inside the sphere, so allies can be excluded.

Failed saves remove actions through incapacitation

A failed save imposes both charmed and incapacitated while the effect lasts. This is powerful control because an incapacitated creature cannot take actions or reactions.

Concentration is required

Taking damage can threaten the entire effect through concentration. Protecting the Shinobi's position is therefore important.

Targets get repeat saves

An affected creature repeats the Wisdom save at the end of each turn. Taking damage also gives it another save, so allies should consider whether attacking a controlled target is worth the chance of freeing it.

Long-rest resource

World of Illusion is not a routine every-round technique. Its once-per-long-rest limit makes it an encounter-defining resource.