/execute positioned as is completely useless, because of /execute at.

To reproduce:

1. Type /execute at @a run particle minecraft:flame into a repeating command block.

2. Type /execute positioned as @a run particle minecraft:flame into a repeating command block.
   -> Observe they do the exact same thing, making having both useless.

Neither, by themselves, change the actual executor. Both only change the position of the execution.

Possible fixes:

1. Removing /execute at. Not ideal, as it is shorter and easier to type.

2. Removing /execute positioned as.
   This is a better solution, as it removes confusion.

Also: 'positioned' was originally 'offset', as it offset the entity's position, which is what it does now.

The only reason it's now called positioned, is most likely because of 'positioned as'. But that feature is now obsolete, so I am in favor of bringing back the old behavior/name of 'offset' instead.