For LFP you can supposedly pack the cells very tight, as they require less thermal management if I understand correctly. And you’re HAVE to do this optimisation for LFP to have decent pack level energy density.

For Li-ion cells, you need that empty space for cooling of the battery cells anyway.

And Tesla has demonstrated that cylindrical cells can contribute to the structure in a structural battery pack.

So for Li-ion I don’t think cylindrical cells are worse. There’s just different trade-offs.

But yeah, one of downsides it can be hard or impossible to replace individual cells if they have problems.