"The Empire is the Law"
"The Law is Sacred"

What does it do?
This mod changes the name of "Gold" to Septim and sets the weight to 0.01. It also gives them the "GiftUniversallyValuable" keyword, which I noticed WACCF did and thought made sense. Nobody is upset to see a bit of extra money.
Also it's an .esl flagged .esp, so no load order slots are wasted on this.

How did you come up with the weight?
The Roman Aureus. In the time of Julius Caesar, it was about 8 grams, which is about 0.018 pounds. By the end of its life as an issued currency it weighed about 5.45 grams, which is about 0.012 pounds. I went with the later one, given the age and decline of the Septim Empire, and rounded it down because the extra 0.002 is kind of pointless and doesn't look very neat.
Also, a neat coincidence is that with this mod 100 Septims weigh 1.0, which is the same weight/value ratio as a vanilla gold ingot.

What is the point of this?
I like to pretend seeing "Septim" instead of gold creates IMmErSiOn. It probably doesn't, really. The weight also falls under the same IMmErSiOn umbrella. Neither change really notably improves the game on its own.
Personally, I use this because I like the additional pressure it creates for me to actually use my gold. Septims sitting in my inventory with this are useless weight and the only solution is to spend it, therefore converting the useless weight into useful weight like potions.

Other Mods already do this, you worthless hack!

A bunch of mods include this as a feature, and there is at least one other standalone that does the same thing. Mine is heavier, and is based on being a giant fucking nerd with real coin weights. Mine is also .esl flagged, which the others might not be, I haven't checked.

Like I mentioned before, there is ultimately no super compelling reason to use this mod, either over its "competitors" or in the first place. This is my implementation and what I personally use, and I chose to share it for others who may like it.

Compatibility:

This mod:

• Edits the name and weight of the vanilla "Gold001" misc item and adds a keyword.
  

And does nothing else. Other things that edit "Gold001" will conflict. Nothing else will.

My Other Mods
If you like this one, perhaps check out:
Thalmor Use Elven The Thalmor use elven weapons at minimum.
Jenassa in Chitin or Jenassa in Chitin - SPID To give our mercenary armor that suits her.
Irileth in Chitin puts Irileth in chitin armor.
Aranea of the Temple or Aranea of the Temple - SPID Dunmer priestess wears the robes of the dunmer priesthood.
Aela in Wolven puts Aela in the wolven armor of the Companions' Circle
Dunmeri Ghosts - Dunmeri Gear To make sure Barenziah's Crown was escorted by true dunmeri warriors.
Civil War F Off - No Season Unending Makes the Civil War, um, "fly" off.
Elementalist's Fletching If you'd like some elemental arrows in your life.
The Jarl's Household Guards To give the Jarl's personal guards a more unique feel.
Imperial Honor Guard Gives Tullius some proper protection.
Waymark - A Road Signs Mod Adds more signposts and road signs to Skyrim.
The Redoran Council Guard Gives the Councilor of Raven Rock's personal guards a more unique feel.
Climate-Aware Stormcloaks Reintroduces the cut sleeved Stormcloak Cuirass by giving it to Stormcloaks in cold locations.
Necromancy is Taboo Upstanding members of society no longer sell spells from the reviled and feared school of Necromancy.
Stones of the Stars A Morrowind and Oblivion inspired Standing Stones overhaul.
Children of Nirn A Morrowind and Oblivion inspired Race overhaul.
Jailors and Turnkeys Differentiates the jail guards from the generic guards.
Civil War Officer Corps Adds Stormcloak and Imperial Officers to lead patrols.
Faction Specific Loot - Eagles of Alinor Handcrafted overhaul of Thalmor loot pools.
Faction Specific Loot - Children of the All-Maker Handcrafted overhaul of Skaal item pools.
More Dangerous Enemy Poisons Enemy poisons last longer and are more dangerous.
Fletching - Craft Arrows Anywhere New power to craft arrows wherever you please.
College Ghosts - College Robes The College Ghosts in Labyrinthian now wear College robes.
Faction Specific Loot - Blades of Mephala Handcrafted overhaul of Morag Tong item pools.