The ingredient you might be missing for how common the CLT is applicable is the following: in most complex systems (e.g. biological systems), any variable you measure is likely influenced by a lot of other hidden variables. Because there are so many variables at play, each effect is likely to be small, and the way their effects are compounded is likely somewhat additive (this one comes from things like series expansion). Hence summing up effects between variables must be relatively common and account for the bulk of the variation in a response variable.
A last bit is this: most statistical methods like the linear model are relatively robust to deviation from the normal distribution. So, you don’t need exactly a normal distribution, you just need close enough. It turns out the CLT often produces “close enough” quite quickly (i.e. with a few variables added together).
It’s not just UI wise.
They explain it on their website : their internal logic for a document is based on OOXML logic, while LO is rather based on a ODT-based logic. So compatibility with Office is more straightforward in OO (though we know Microsoft is not quite exactly following the OOXML norm, so still not perfect…)