It is functionally short for “You may play this from your trash for its flow cost. Then banish it.” 1. Banishing the spell in this way is a delayed replacement effect. If the spell would leave the chain after becoming a finalized chain item, and leaving the chain wasn’t instructed by its own execution, banish it instead. See rule 367. Replacement Effects for more information. See rule 389. Delayed Abilities for more information. 2. Playing a spell for its Flow cost does not change the timing at which it can be played, nor any permissions for the spell aside from the zone from which it can be played.
