Three things:I cannot stand D&D combat that exists as a resource drain but not an actual threat. If there’s nothing but a few spells or hit points on the line that will just regenerate after a nap. Just roll a few dice and tell me how many spells and hit points I’m down until sleeping. Don’t make me waste an hour or more rolling dozens of times when there’s no real stakes. No stakes, no tension. No tension, no excitement. No excitement, no point.
1. Sometimes it isn't obvious there's no real stakes until after the combat is finished or mostly finished and you-as-players (both in-character and out) come to realize these foes really aren't/weren't up to your usual standard: either they were glass cannons or were presented (or perceived) as being more of a threat than they really were.
2. In any system where a really bad (or good) single roll can have major consequences, e.g. a fumble can cost a warrior her weapon or cause a mage to blow up his own party, IMO it all has to be played out.
3. In some editions and systems, resource attrition is a much bigger deal than it is in 5e D&D, meaning these little seems-like-nothing encounters now could have a significant impact later.
Agreed. The only time predictability is good is on those few occasions where they're surprised things in fact worked out the way it initially appeared they would.Predictability is monotonous, boring, and undesirable.