Yes, but when we want to store something in the range of million years, it is a bit early to say that 30 years are sufficient as a ultimate proof that nothing leaks.
Now I believe it can be done safely, but only if monitored all the time with good care. But that is expensive and humans tend to skimp.
You don't need nuclear waste to be stored for millions of years, after a hundred or so anything of exceptional danger has decayed and what is left will be such a low level of radiation that common clay bricks are just as much of a risk. The "hotter" a nuclear material is, the faster it decays, and materials that remain radioactive for thousands of years are not especially radioactive.
Again, when you bury uranium half a kilometer deep in an area with no aquifer, how will it ever result in contamination?
The only real scenarios are deliberate excavation, and a meteor impact directly on the waste repository. Neither of which are particularly likely scenarios.
Because the ground is not static. And we are just starting to understand what is going on down there. So yes, there are sites that remained quite unchanged (like with the natural fission reactor), but personally I remain sceptical with such statements.
Are we supposed to hold off on developing the only geographically independent and non-intermittent form of clean energy because of some vague nebulous fear that waste buried half a kilometer deep in bedrock will come back up to the surface and harm people... somehow?
No, but maybe we should not pretend all is super safe and always will be, when we cannot know currently.
Or rather we do know that the initial promises of reactor safety were also quite overconfident. So people assume the same of permanent storage of the waste.
And what you linked is still under construction. We don't know yet, if it really works safe long term, or if there will be future costs.