Can a Level 6 College of Swords Bard (with an extra attack) utilize the +10 movement by moving 30 feet, attacking with a ranged weapon, moving an extra 10 feet, and then attacking with a melee weapon? I’m told you can only add +10 movement if you attack first. You need to attack first
— Jeremy Crawford (@JeremyECrawford) April 24, 2018
Sorry, I don’t understand. Blade Flourish says “Whenever you take the Attack action on your turn, your walking speed increases by 10 feet until the end of the turn…” In their example they made a ranged attack before moving the final 10 feet. Do they need to make *both* attacks? Your understanding is correct. I was affirming that their example was also correct: an attack precedes the extra 10 feet.
— Jeremy Crawford (@JeremyECrawford) April 25, 2018
Another instance where JC’s response (the initial one) *didn’t* properly address the issue at hand and only served to provide further misunderstanding… even though the question, as phrased/presented, made it clear what the issue was: do you have to attack *before* moving (at all; that is, before any movement, the Attack Action must occur first) in order to use that bardic ability(?). These are the moments when/where his critics are completely on-point.