Total UI Inconsistency with decimals in Illustrator
1 v 22.0.1
Most of the Features in Illustrator have inconsistent number of decimal points.
New document size  3 decimal places  0.001
Artboard size  2 decimal places  0.01
Artboard position x,y (in the same window)  1 decimal place  0.1
creating new rectangle  4 decimal places 0.0001
Object transformation  3 decimal places 0.001
Rectangle angle 2 decimal places  0.01
Rounding corners  3 decimal places 0.001
Split into grid  2 decimal places 0.01
Offset path  4 decimal places 0.0001
3d revolve angle 0 decimal places
3d Extrude & Bevel angles 2 decimal places, 0.01
3d Extrude & Bevel  extrude depth  2 bevel height 0 decimal places
3d Rotation everything 2 decimal places 0.01
drop shadow dialogue  2 decimal places
Move dialog  4 decimal places
Pattern  4 decimal places
Blend  2 decimal places
Let's look at the example user journey:
In my workflow I am building an illustration of isometric sport games layouts.
As Illustrator has an working area size limitation i am forced to keep the illustration in certain scale. and for smaller objects I have to create bigger versions of 3D elements, then through symbols/CC library scale them down. Otherwise the limitation in number of decimal places of the 3D effects doesn't allow me to keep the proper object shapes.
The number of decimal places in Transform tool is 3 (minimum 0.001)
The extrude Depth field has a soft cap for 2 deciamal places and minimum value of 0.01 pt
the Bevel Height for some unclear reason is limited to zero decimal places  1pt
Both have to be 3 decimal places a minimum value of at least 0.01pt ()
5 comments

John Miller commented
I don't understand why we don't have this decimal problem in Indesign. Why does Illustrator has to round it up?

John Paulhus commented
I really want 4 decimal places to be the standard across all Adobe CC programs. How else could we get a perfect 16th (.0625)?

Christopher T. Calhoun commented
The issue in particular I have is that artboards only have 2 decimal places in inches. Float that ****** out to 3.

Valerii Mamedov commented
Thanks for the answer, I hope you will bring it to a logical solution flexible and consistent.

Thanks for compiling this and sharing details of your workflow. It definitely helps us understand the issue better.
As we gather, there are two parts to the issue  one, there are different decimal limits in different places, and two, this difference is leading to precision related problems when you use scale factor in your measurements. For the first part  it would have been easy to solve, if we had just one unit to deal with. Illustrator handles 8 different units simultaneously and each have their own logical scales. Units like Pica or Q/Ha, or even Inches, require a different treatment than mm/cm. An input in one unit, has to be converted with its best possible accuracy to the working unit. This is not to say that anomalies do not exist. And as you've pointed out in the examples, there are different decimal inputs limits in different places.
What we are thinking is to build a consistent decimal limit, for each unit in all places. But it would still be possible to see different decimal limits for different units. Maybe, we even expose decimal control for different units, in the UI. Maybe.
For using scale factor, building a consistent decimal limit for each unit, should solve the problem to an extent, but ideally there needs be a different solution for that problem and we're exploring different possible options around that.