Those who do not know History are doomed to repeat it. Back in the day of the OSI stack, the telecom guys were huge fans of binary protocols. The arguments were exactly those described here on HN: they're easier to implement; with the right tooling, they're just as readable; they're more efficient.

The fact is, on the application layer, text based protocols wiped the floor with binary protocols. The answer is in the little details, which everyone knows is where the devil spends its time. They are not easier to implement, because they're more difficult to debug (and because text parsers are, let's be honest, a solved problem); they are not as readable, because debug tooling is never perfectly implemented and never ever present in every system; they are more efficient, but at this layer the efficiency does not pay off (i.e. the size of the HTTP header leading that 5MB image does not really matter).

One of the comments here pulled a comparison I did not remember any more: SS7 vs SIP. Go and have a look at both protocols. They are both mature, so you don't really need to wait for the fantastic debug tooling to appear. Study both ecosystems and then form your opinion on binary vs text application protocols.