blog: add the practical benefits + the honest cost note to "Played in the open" (#151)

Three additions, kept plain and rooted in real value (no pitch):
- "A home for your clips" — platform-agnostic store / share / sort; your console
  forgets clips in two weeks, Vera keeps them (folded the memories/covers beat in).
- "Your clips can give back" — sharing builds Vera's library: featured in posts +
  learned-from over time. Grounded in the consent given at upload; pull anytime. …