A trucker hitch is a lashing, a poldo tackle is a quick adjust sling. They're kinda similar in that they're both a z rig, the rope going thru an eye for mechanical advantage, but the difference is that the trucker hitch is far more useful

when i first saw the poldo tackle in a knot book i couldn't see how that could possibly be worthwhile, i mean there's really no good way to pull it tight. I remembered it simply because it's seeming uselessness completely baffled me.
The poldo tackle basically acts as a super fast way to adjust the length of a sling. Since all parts of line have an opposing line canceling out forces, you can simply slide the two hitches in or out super easy when it's unloaded and when it's loaded it'll stay in place. You can build it with pulleys even, doesn't move once it's loaded, it's kinda creepy. Makes a decent belt in a pinch where you can adjust it tight in a split second and make it big enough to slide down when loose, but where it can really shine is when attempting to rig awkward heavy unbalanced loads. A great example in construction would be a fabrication or piece of equipment that ideally needs to be leveled in both directions to install or lift.
Everyone here would simply bust out bull rope and tie a spider leg, but you can't do that in construction so come alongs and chainfalls are often used for load leveling below the hook. You're often limited to the gear on hand, and so you may only have some slings and shackles to use. That's where it can save you, by using a poldo knot with a rated rigging sling using shackles to make your connections you can use a sling in what's a basket rated way and can be adjusted for length a bit.
The danger in its use is that if the sling is unloaded the knots can slip, so you should lash them together (rope, zip ties, duct tape, etc) if that's a possibility. Also make sure the shackles are flipped so it can't unscrew the pin, so you put the pin in the eye.
I've used it on rigging pipeline fabrications, the first time on hour 16 or so on a tie in as a helper. We fabbed everything up, and the guys couldn't figure out how to rig up this big awkward 90 piece, no matter how they adjusted the slings it wouldn't go. I went up there, had it all rigged in a couple min with a poldo tackle (never actually trying it before on actual serious rigging), picked it up and down a couple times to set it and to adjust the straps around til it was at the required angles both ways, and boom i was almost as amazed as everyone else when it worked perfectly, all of us watching it in action for the first time in wonder
It's really cool that it actually works, but you really need to think outside the box to apply it sometimes since it's such an odd thing. It is technically a tackle, but unlike any tackle I've ever used you don't really get mechanical advantage with it, it simply stores line. It works with wire or chain, and it's super fast and easy to adjust. I think on most stuff rope is gonna be the easiest but if you're limited to slings it can be super handy. And it makes a surprisingly decent belt, leave a tail a bit long so you can add a half hitch or daisy chain for security
