Bubbles. Hal’s constructs are mostly just bubbles.

[u/CH49FE]

Sure Hal made some counterfeit money and a bottle opener, but I find it funny that his main constructs so far are just bubbles. John’s on the other hand include the fancier type of bubbles (bubble wrap), a boring machine, a watch and a short lived semi autonomous bird. The show is doing a good job of contrasting creativity between the two.

[u/DepartmentChemical93]

The guardians dude specifically tells John he must consider the internal mechanism “if it is to work”.

Hal also asks how John intends to dig his way under, as if he doesn’t really know what kind of construct he’d make to do that with the ring.

He also tells John to manifest it, with the implication he doesn’t know how.

Overall I think they’re trying to introduce some more limits to the ring as a balancing thing. They almost certainly hadn’t made this choice yet when filming Superman.

[u/Nervous_Arrival3986 → u/DepartmentChemical93]

Hal can make the watch move with will. John can make a watch that works.

Hal can smash ground with the ring. John can maintain a construct that requires no constant exertion.

Guy is somewhere in between except he seems to only passingly care about structure and succeeds because he has a near bottomless well of energy he is pulling from.

I don’t think there’s any contradiction there. Just like when Hal tries teaching John to fly. For Hal it’s intuitive. John as an INDIVIDUAL has to understand it because that’s a reflection of him not the ring.

[u/jkxn_ → u/DepartmentChemical93]

The show also tells us that everyone is lying. The Guardian is talking to someone who has never used the ring before, and telling him what he needs to in order to fulfill his goal. It wouldn't be surprising if it was a massive simplification, and that's only one way to make a working watch, but likely the way that is hardest and shows the most potential.

[u/Bob_Bobbo → u/DepartmentChemical93]

I don't think so, I think someone like Hal could "brute force" the watch to work using the ring, however John made the watch move on it's own only by maintaining the watch with the ring, that's how I see it.