You'd think that. Writers ignore it, readers don't.
They tear that kind of stuff apart. It's not exactly beaming people (I personally don't like teleporters, and that's a little too advanced for the setting I want to craft as paradoxical as it sounds).
I suppose it depends on the fandom - Eclipse Phase fans have had detailed discussions on the exact science of causality violations and the practical uses of them, but I don't see Trek or Wars fans arguing that the solution to every problem is to fly back to last week and nip it in the bud.
It's more like humans learn through this technology (which is originally designed to solve the energy crisis) that when you coat a non-organic substance is coated in it (I'm thinking about making it more specific than that, probably paladium coated or something) it can basically bore their own wormholes and cross large amounts of space in a few minutes (making temporal issues non-existent). It is fairly slow in the energy-collection part of it though. Taking hours to charge out in space.
For that... well, honestly, pick your handwavium and run with it. In general, having an idea how it functions but not the exact principles behind it is fine - after all, if you knew the science behind how it works, you'd just build one and cash in, right? As far as the specific implications of wormholes go... well, depending on how restrictive or difficult it is to create them, and whether or not they can easily be moved at high velocity relative to each other, you're mostly worried about informational
violations of causality. Which means that stock markets might be a little complicated in your world, but there aren't likely to be masses of people spending their vacations killing Hitler.