Using hilton gift card is becoming too much hassle. Repeating my post above that there are two kinds of hilton properties:
1) Knows how to accept hilton gift cards
2) Does not know how to run a hilton gift card - instead accept as a generic Amex gift card

At 1), we can use the full amount without a problem.
At 2), there needs 15% buffer in case of incidental charges. $50 becomes $43 because of this buffer (0.15x$43=$6.45 needed). And the fund doesn't settle for the next couple of days, so we cannot reuse the card to pay, say for $6 out of remaining $7, immediately after.

The strategy is, if you find $50 fails and only $43 works out of it, then redeem it, keep the card and use the remaining $7 at the next hotel stay. On the next stay, if $7 fails but $6 works, use it and throw away the remaining $1. Not worth to fight for $1 and honestly, we all got the card at a little cost anyway.

Would be nice to run $43 at check-in so that by check-out, we can drain another $6, but hotels at cat 2) tend to struggle and let us try at check out. If hotel says they don't accept gift card, they are cat 2), and ask them to still try. Some hotels may say they only accept apple pay. In my experience, it doesn't change the dynamics of $43 meaning they are still cat 2). At least they are apologetic with the issue and let us use as many cards as possible, even 10+.

Also, try only at US properties. I'm hearing horrible stores at foreign properties - many people say Niagara Canada hotels accept it as 50 CAD and take the gift card away. And it's too much uncertainty to use at a foreign property when we have to provide the amount rather than auto-draining the card.