Why do some Christians use a period instead of a colon in verse references? In the same way some countries write $1,000, some write $1.000, what do we learn when someone uses this alternative way of writing out verse references?

I have one lecturer that prefers this. i.e. They will write Jonah 1.5 instead of Jonah 1:5. I am wondering if anyone can enlighten me as to where this tradition comes from? i.e Who made it popular, does it reflect this person comes from a particular background?
There's probably no general explanation for the different reference styles. Both are just as easy to understand, but using the colon is the more common.

Wikipedia says that the Chicago Manual of Style specifies a colon while MLA style specifies a period, but only a tiny fraction of Bible verse references would be from people strictly following either style. More relevant to Biblical studies and theology, the SBL Handbook of Style uses colons.

In recent years the period has probably become more common because on most mobile phone keyboards it's faster to type than a colon, which usually requires switching keyboard mode.