Your private key can be stored in a bank box, or a small fireproof safe.
It's not convenient to store several years of backups in those places.
LTE is not 4G. Here in Norway, one provider is in some trouble for falsely advertising their upcoming LTE offering as 4G.
Nokia explains that LTE is not 4G here.
APPLE is the distributor; THEY have to offer the source. And impose no further restrictions.
They don't offer the source, and they do impose further restrictions on distribution. Hence, TFA.
Computer Science is merely the post-Turing decline in formal systems theory.