What does "my point being" mean?

I have heard someone say in a conversation, "Well, my point being,,,". As an English learner, I was puzzled but assumed that it was roughly the same as saying "My point is that..." or "Here's my point:"

Even if my guess was right, the phrase strikes me as a bit odd. Can anyone elaborate on the meaning/usage/gramatical explanation of this phrase?

From The last will and testament of Gen. George Washington (1800)...

... my intention being, that all accounts between them and me ... shall stand balanced.

Note that words like intention, meaning, reason, point all overlap in various contexts. And as this 1727 instance shows, point has been around with this reason, argument sense for a long time.

Presumably what OP finds "odd" is the word being, in a construction where the more obvious verb form would simply be is. To be fair, Robert Noggle at Central Michigan University also says "the reason being [some reason]" is somehow invalid (he certainly doesn't like it), and maybe there are others who feel the same. But I disagree - it seems like perfectly standard English to me.

Arguably in some contexts the present continuous "being" emphasises the ongoing nature of whatever is being referenced more than simple present "is". For example, "My point being that X" could imply some "insistent" sense of "My point continues to be / has always been that X".

It looks an absolute construction.

Among the modifiers that we use to add information to our sentences, the absolute phrase is probably the least used and the least understood. In form, the absoute is a noun phrase—a noun headword with a postnoun modifier; it adds a focusing detail to the idea of the whole sentence.

Here is a description I found from the web:

"Being" (accompanied by its sidekick "point" or not) is often employed in an absolute construction attached to a complete sentence. As such, it is acceptable. For instance, we might write: "The legislators went ahead and passed the measure, the expectation BEING that they knew the governor would veto the bill in any case." The absolute construction misfires, however, when it is not properly connected to another sentence and it's left hanging out there as a fragment. The point being that you don't want to do that. (See?) This is not say, however, that fragments are always an evil thing; sometimes and occasionally, they serve a stylistic purpose (usually drawing attention to themselves). From Here

Wikipedia Article

Here's a good description of use.

Or 'being that' could possibly be used like a compound conjunction. For more on that, see Swan. In that case, it is used interchangeably with because and since.

This adverbial construction describes the circumstance of the main statement. It has probably been introduced into English on analogy with the so-called absolute genetive and ablative in Greek and Latin, where both ‘point’ and ‘being’ would stand in the genetive or ablative case.

I ordinarily hear this at the end of longer utterances as a summary of what the speaker has been saying. Think of it as preceded by a dash: "... yada, yada, yada—my point being that &c".

I've occasionally heard it at the beginning of an utterance, where speaker A is responding to speaker B's objection to A's preceding argument. In effect, A reasserts his own previous argument, implying that B has missed the point A was trying to make. Here it generally has an argumentative tone, and often a somewhat whiney one.