Anime studios rarely announce cast members without wrapping them in context—a character reveal, a story beat, something that explains why you should care that voice actor X is playing role Y.
The Tougen Anki announcement skips all of that: eight names, eight voice actors, no character descriptions, no arc summary, no reason given for why this particular stretch of the story warranted this particular scale of promotion.
That absence is the story. What you're seeing is a studio testing whether the franchise has moved past needing the source material as justification—whether the cast itself, the fanbases those eight voice actors carry, can function as the draw.
Voice actors have become brand assets in ways they weren't five years ago. A single popular seiyuu can move merchandise, streaming numbers, and fan community engagement independent of plot. This mirrors how the music industry shifted when Spotify's payouts made album sales irrelevant—artists started treating Spotify placement as the primary product, not the residue of record sales.
The real question isn't whether these eight castings are good for Tougen Anki. Whether Tougen Anki has already become secondary to maintaining those eight actors' visibility and earning potential. Notice the next time you see a creator promoted without reference to what they actually made—whether the person has become bigger than the work, not because they're talented enough to transcend it. Because their existing audience is easier to monetize than convincing new people the work is worth their time.