[paxys]

All the examples of question comma on the site can easily be written as two sentences though.

[yarg]

And most sentences with a semi-colon could also; it's often a matter of personal preference without well-defined fixed rules.

[dragonwriter]

> And most sentences with a semi-colon could also

Well, yeah, since the difference between a comma and a semi-colon is the latter joins independent clauses, it is necessarily the case that any semi-colon use for joining (as opposed to its use in, e.g., lists) can be replaced by a period, you just lose the indication that the two independent clauses are tightly associated.