What if it is only mentally?

Same to you!

With waaay less work.

And I didn't illustrate it very well but there's a lot you can do with really big raw damage numbers as a player.

For example the biggest it I had during the play test was over 200 ( split between 4 targets for 12 hp total)

Exactly! which will make designing uber bosses etc easier for an inexperienced gm.

It doesn't have to do with the cap of 3

Even if there are more points on the scale 4-5 whatever

Knowing your player is likely to hit x thresholds which directly translates to y% of the creature hp simplifies encounter design

Which at the same time guaranteed one point of damage on hit prevents hitting the difficulty with no results.

The creature with fourteen h p isn't gonna be brought down by a group picking one hit away at a time. While the creature is guaranteed to be hitting severe thresholds.

That's how it exists in the beta aswell. Contact guarantees one damage.

I understand I might not have been clear.

But I guess another way to put that the messages is No party of low level p c's is going to be able to kill a creature with damaged thresholds higher than their maximum damage.

Sorry to be superlong-winded.

I love my big numbers . I live for the dice kaboom. pathfinder 1 till I'm in the grave.

But.
It's just a really accessible design.

Dagger heart gives an easy way for people to design their own encounters, top to bottom. With out hours of balancing.

Its powerful tool for the gm.

By looking at distribution curves for their players' damage its easier to estimate the maximum number of hp damage out by the party

With x change to hit, y chance they can hit 3 hp, I should be sure my adversaries are at least z hp for a dramatic encounter.

So there's kind of that soft power lock on Adversaries a pc can do toe to tow with .

unless of course you tilted towards doing everything to increase your number of die rolled per attack. (True dps builds)

as monster thresholds to go up it takes more and more to hit that Severe damage threshold.

This has the interesting implication of higher level monsters are not take damage from low level pcs.

Obviously, it's poor balancing to put an archdemon against a whole bunch of fledgling adventures

There are some abilities that allow you to split your damage total among multiple targets.
Ie
One of my favorite beta builds was actually a wizard with the painful d20 weapon with some of the aforementioned spells.

With proper planning.
It became I hit all targets in range for 3 hp.

I get you, it's an adjustment

Spells like wizards parallela
giveways to, get every bit of total dmg die out

damage can always be abstractly described as a dm

It also prevents the classic "my player killed my boss before they took a turn" and "my pc got one shot out of nowhere"