Yes & no. I'm hoping (after the normal weekend lull) others will chime in & give you better input.

I used to reserve rooms (before Plat) w/ award at the Grosvenor Square Marriott in London & think I had to pay 50-70GPB to secure an exec room (and they never told me about the exec lounge, btw - but the room was fab; it did include bkfst in the rest though, even on the weekend). The exec room I got was like a mini-suite & given UK/US exchange rate it was worth it to me, even though the room was 'free'.

My understanding is as Plat you get upgraded to 'best available' but quite frankly who knows what that means in Hawaii (or any Marriott for that matter). I've been Plat last year & this & it's all over the place.

My guess if is you want to definitely 'secure' a fab room, you might have to pay the $$. But you might want to call the hotel & chat w/ them re: what you'd actually get & then determine if it's worth it to you. Certainly worth the phone call.

Cheers. Sharon