What is "Currency"?
Currency is the means to obtain needs and wants.
We are always missing things. Be it essentials, like food, clothes, and housing. Or extras, like whisky, jewelry, or a vacation.
How to obtain all these? They're not free!
Currency is an object of agreed value. We trade the currency in exchange for those goods.
And that's why
Physical Currency will end,
with the Coming of Moshiach, when all physical needs will be met, plus much more.
works on the same principles:
Living in this physical world, our spiritual soul has a constant need:
To connect with its Father in Heaven.
This need can only be fulfilled by:
Acquiring Love & Awe of G-d, and
"Spending" them on doing His Commandments
That's how it works in this world.
But what will happen in the
(after the Messianic Era)
when infinite revelations of G-dliness will prevail on earth?
At that time we'd say "so long" to longing for G-d, for we'll be completely united with Him. Not as a separate entity but one and the same.
That will mark the end of Love & Awe of G-d.
This would also mark the last and ultimate expression of the sign:
"Moshiach won't come until
money runs out of wallets"
Moshiach will come before those infinite revelations hit the world.
But Moshiach comes in stages.
The ultimate stage of his coming – the fullest context of Moshiach's arrival / his ultimate mission – is the revelation of G-d in this world.
And that's when there'll no longer be spiritual money (Love & Awe) in the hearts (wallets) of people.
Now compare this ultimate state with our current state, at the end of Exile:
are also telling the same story as what we've learnt in this topic.
As a cute message.
Currency symbols have a line going through them
Most currencies have this line horizontal
The USD has the line vertical
Sometimes this line is shown as a double-line
While the symbol represents the particular currency, the line going through it represents connection. The connection to what you can buy with the currency.
These currencies represent physical value. Therefore the line is horizontal, representing a connection on the physical realm only.
The US Dollar has associated itself with G-d ("In G-d we trust"). That's reflected in the line being vertical. A vertical line symbolizes a connection between the physical and the spiritual. Not that the USD achieves any such connection. This currency, like its peers, is still in the physical realm. It's only because there's an association with G-d that this line is drawn vertically.
But remember, every physical thing has a spiritual origin.
The origin of currency is the Love and Awe of G-d (that's how it works in Heaven). Hence the double line, one for love and one for awe.
On a deeper level, this line (or double line) supersedes the currency. Crosses it out. Already telling the ultimate fate of physical (and later on spiritual) currencies.
NOTES & REFERENCES
Only way to connect to G-d is via His Commandments: Tanya end of Ch. 40.
Infinite revelations of G-dliness will prevail in the Next World: See Isaiah 30:20, 52:8, and 60:19.
Love and Awe of G-d will "not apply" in the Next World: See Talmud Nida 61b, that the Commandments (Love and Awe of G-d included) will be nullified in the "Future" (לעתיד לבא). According to Tosfot, "Future" refers to the time of Resurrection of the Dead. According to Rabbenu Nissim (הר״ן) "Future" refers to a later time (the Seventh Millennium -- see Tanya Ch.36 in the comment there).
Mashiach will come before any revelation of G-dliness in This World: Mashiach will be there at the end of Exile, before the Redemption. See Talmud Sanhedrin 98a that Mashiach sits at the entrance of Rome among the poor and inflicted. Also see Rambam, Laws of Kings Ch. 11: (c) Mashiach will not need to make any miracles. (d) "If a king rises... He will strengthen the observance of Torah and fight the wars of G-d".
Mashiach comes in stages: See Rambam ibid:
Presumed (חזקת) Mashiach, when he performs certain actions during Exile (causes all the Jews to follow the Torah and strengthen it, and fights the wars of G-d)
Certain (בודאי) Mashiach, if he had won those wars, built the Mikdash, and gathered the dispersed Jews.
Then he will adjust the whole world to worship G-d together.
Similarly we find different periods in the Future Times: The "Days of Mashiach", "Resurrection of the Dead", the Seventh Millennium", and the "Next World".
The ultimate and final goal of Mashiach is the infinite revelations down in this world: See Tanya Ch. 36 about the ultimate purpose of Creation. Mashiach is the "Final Redeemer" who will bring this revelation about, similar to Moses, the "First Redeemer" who brought about this revelation temporarily, on Mount Sinai -- see Midrash לקח טוב on Exodus 4:13 and Zohar Pt. 1 253a.
A vertical line represents a connection between the physical and the spiritual: Hayom-Yom p.26 (8 Adar 2).