It has everything to do with internal representation of data in general, and floats are one specific example that turns up quite regularly. Sometimes one machine has some data, and you need to transfer that to another machine. Sometimes the internal representation of that data will be different. Sometimes you can't simply "send the bits" and have it work.

So in those cases you need to go through an intermediate representation, and then the question of conversion arises.

So sometimes, when sending a float (as a single example) from one machine to another, you have to go through conversions, and one way to do that is to generate a string representation. The point here and in other comments is that many people think this is easy and obvious, but in truth it's hard and full of pitfalls.

You said:

> I do not understand why would you ever round trip floats through text.

I'm trying to explain that. I have some experience of the issues involved, and was trying to share my experience. You are dismissing it, which is entirely your choice, and in that case, my comments are here for others.