[Kaimetsu]

If I'm holding a sword in front of me then it would be unwise to try to get close, lest you skewer yourself. Theoretically you could knock the blade away first, but it's risky, and you'd leave yourself open to a retaliatory slash.

Plus, is it possible to block with those hand daggers?

You're right about the armour, though. That'd be a real problem, but I could at least put you off balance or flinch you.