It’s insignificant that Catholics picked the books of the Bible because it’s easy to tell which are inspired and which aren’t, right?
The Gospel of John was the last book in the Bible to be written. Before and after it was written in the 90’s AD, many other works that claimed to be inspired were written as well. The Shepherd of Hemes, for example. James wrote a gospel as did Peter. Some churches thought these writings were inspired. Many churches also rejected Revelation and Hebrews as un-inspired. There was little or no consistency with the early church on what writings were inspired and which weren’t. In fact there are no less than ten differing lists of what different churches held to be inspired and what they did not.
It took the pope and the bishops in communion with him almost thirty years to finally figure out which books were inspired and which weren’t. It wasn’t obvious or easy. There was no one criterion that could be used. In fact the chief criterion was whether or not the writing matched the Oral Tradition of the Catholic Church!
So, yes, it is significant that the Catholic Church was given the authority by the Holy Spirit to determine the books in the Bible. It’s significant because the Catholic Church had that authority then, and has teaching authority today.