Lambent Plume doesn't work in Temple of Styx?

[Milk]

Hey so I picked up the Plume after the Theseus fight and im clearing the side temple paths in a few seconds but the plume isn't giving me bonuses.

Are the small rooms not counted, or am I supposed to clear these rooms in like less than 2 seconds?

[Orogoth]

Yep, small rooms are not counted, only the final one. I think it's the same for all keepsakes.

[Eizo]

Small rooms not counted. Guess it would become too imbalanced otherwise.

[Seiryuu]

Small rooms don't give bonuses, tested it with Pierced Butterfly; I feel like clear bonuses occur when the room you're in actually dispenses a reward once the encounter is over.

[Goomy]

It seems like the only thing that will kick in in the small rooms (or indeed in non-combat rooms) is the healing buff.

[dragoon264]

But works on boss fight.
While fighting the last boss, I noticed there is a "clock" under the Plume to tell you how much time you have and consumed to gain the bonus. I think there should be better places. And why there is money pot in the last boss place ?