What does it look like when you take 7 damage?
In earlier editions, if someone hits you with a sword and it takes a week to heal from that, then you could reasonably describe that as an impact which resulted in bruising through the armor. That's the sort of physical injury which might heal in a week, and which could result in unconsciousness if you sustained too many of them at once, even if it didn't significantly degrade your combat performance by itself. And if that was the case, then a healing potion (or cure spell) that could instantly reverse such damage would be fairly impressive, and possibly even worth a pound of gold.
The existence of Hit Dice / Healing Surges means that HP damage heals naturally over a drastically reduced time scale. In later editions, where 7 damage heals naturally (without magical intervention) over the course of a short rest, you can't reasonably describe it as any sort of real physical impact. There is no degree of physical injury which is potentially fatal when cumulative, and which can also be completely reversed over the course of (6 seconds, 5 minutes, or an hour); so HP damage isn't substantially physically. Being "hit" for 7 damage means you narrowly dodged, or spent some "luck" to have random debris deflect the attack, or some other contrivance. (We actually have zero indication about what HP actually reflect, except that it definitely isn't physical.) And in that case, a healing potion is like a sports drink or something.
Oh! I I expected some argument about pacing and encounters per day etc etc... not yet another "what is HP?" debate. But fine, I'll play.
See I've been thinking about hp lately, and the nature of D&D characters. And the key to understand hp is not "a sword wound". It's
falling.
A hit in D&D, as you say, is vague. You get hit by a goblin arrow for 1d6+2. What happened? Well, it's not clear. Falling though - that's very clear. You smack the earth at high velocity.
If I (me, the poster, not my PC) jump down 10 feet... I might be OK, or I might flub the landing and hurt myself (1d6 dmg). Jumping 2 stories (20 feet) is a sure way to injure yourself (2d6) and if you land badly, you might die. Once you hit 3 stories (30 feet, 3d6 dmg), it gets really dicey. A fall from 5 stories is usually fatal for humans (5d6), although not always (luck, soft soil, skilled acrobat).
A level 6 wizard with 8 dex, no acrobatics training and 14 con (38 hp) can jump down 5 stories and survive
guaranteed. Heck she could do this every evening before bedtime - maybe it's her "toughening up" routine.
Again, luck is a factor when falling - some people have survived falls from very great height! But that's luck. No one - at least no one without special training and/or a proper landing surface - can fall 50 feet and be 100% fine the following morning,
every day. But most tier 2 5e characters can.
The conclusion I draw is that by the time 5e PCs have reached level 5 or so, they have become more than mere mortals - they are heroes. Not the "the 80 year old man ran into a burning home to save a child" kind of heroes. The supernatural kind of heroes.
