Just to nit-pick, I think he meant number of different translations, not number of languages it was translated into. I doubt there are multiple translations of Little Prince into each of those languages.
What makes it important for this book is that the source is from classical Chinese which is far more ambiguous than say the French that Little Prince was written in.
Consider the first sentence: 道可道非常道 名可名非常名. It's written as two parallel structures, with 道 replaced by 名 in the second half. In both halves, 道/名 could be functioning as a verb or a noun in any of its usages.
Let's consider 道: amongst other things, 道 as a noun could mean road, path, way, principle, reason, skill, art, but also as a general class of objects like rivers, barriers, etc. 道 as a verb can mean to travel, to say, to express, etc. And of course, as a result of this text, 道 stands as a shortcut for the entire text - more than just a principle, but The Principle, more than just a way, but The Way.
Even the other words aren't simple. 可 is often just thought of as part of 可以 to mean may nowadays, but 可 itself means can, may, able to, to approve, to permit, to suit, certainly, etc. 非常 is an odd one, as I'm sure the modern day meaning (extremely) completely throws you off track. 非 on its own means not, wrong, to not be, to blame, etc. 常 means always, ever, constant, often, frequently, common, general, etc.
I'm not saying any of these examples I'm giving now are good translations, but you could, for example, have translations that are diverse and extreme as "the road which could be traveled is not often traveled", "to travel on something that could be a road is rarely the correct way", "travelling on something that might be a road but was not always a road", "the road you may travel on is often not a road" or "the road you may travel on is never the right way". None of these are like any existing translations I've seen, but that was done on purpose, because they're all legitimate (but unlikely) interpretations of the original.
If you look at the meanings given in this translation: "The way you can go
isn’t the real way." In the same repo, Jane English's version is "The Tao that can be told is not the eternal Tao." My bilingual version translates it as "The Dao that can be trodden is not the enduring and unchanging Dao" (James Legge, 1815-1897).
You can see that the linked-to translation has chosen a quite different approach to at least two others. Which is correct? Perhaps all of them, perhaps none of them. There's a reason why these texts are considered so enlightening - there's no one correct answer, you have to really meditate on the meaning and come to your own conclusion.
But anyway, back to the point - the nature of the text means that if you're reading a translation it'll miss a lot of the inherent ambiguities of the text and instead direct your thinking down specific lines. That's why, for this text the number of different translations is more important than number of languages it's translated into.