When other than in multi attack do you find it useful to use attack by percentage?

When I'm blockading a territory but want to salvage some armies from it, I transfer by % instead of by the digits, in case I get attacked. So if I have 20 armies and move 15, but the opponent killed 4, I will have only a single army left on there. But if I transferred by 72% I would still have 3-4 left on there.

That's a pretty common use of % attacks, I can remember making % moves at other times but I can't remember at the moment.

Counterattacks.

When I make attacks right at the bottom of a set of orders from one territory to 2+ others I do it by % because I don't want to be attacked earlier in the turn, and only have enough armies left to execute one of the 2+ attacks I ordered.

Say you have just broken the enemies bonus, and want to carry on your attack, but there are 2 territories you could attack, both of equal value but both needed. then you would delay until the end if possible, and attack one with 50% and the other with the troops left. (this doesn't only happen once you have just broken a bonus, but any-time there are 2 territories and you want to hit both at the end of a turn, you can split you armies 70% and 30%, but most usual is 50%)

I games whit high income/lot of armies, for example those who can occur on USA Big, I often use %-tage attacks instead of numbers. Not for any of the reason above, but because it\s simpler and quicker for me to do it that way. e.g if i\ve 342 armies next to 4 territories I want to take I`d attack the 1.st whit 25%,the 2nd whit 33%,the 3rd whit 50% and the 4th whit 100%.which would give approximately equal attacks on every territory and I won`t have to do any math and save a lot of time/effort.

in games that are not multiattack i almost never use attack by percentage. usually there are ways to get what you want without it.

I'm missing this in Season VIII

Billy-Walsh-like. If I can' be sure I'll be attacked, or how hard I'll be, and I want to attack or maneuver several times from a same land later in a turn, percentage is the way to go. It allows more flexibility, sometimes it even makes it possible to blockade on your front without risking a huge spoil of armies in case your opponent doesn't launch the hard attack you expected. Say, if you expect a loss of 20 on defense and you have 30 on the area, , you want to let around 6 units for a blockade and fall back around 4 accordingly. If you command a 40% fall back instead, in case you guess was wrong and the strong charge didn't come up, you'll retreat around 12 units and lose 18 instead of 30, which is more than you wanted but not as harsh as losing 30 the same way.

Anyway, that's an option you always want to keep in mind. Percentage moves are useful indeed.