Are colors saved to CC Library currently useless in AE?

"you haven't worked with the sort of Creative Directors/Marketing Directors that I have!"

I deal with corporate livery rules every day, written for print with Pantone spot or foil embossed logos, and applied to everything from TVCs to YouTube - plus CAM specs that define color with RAL paint codes. I just make stuff that looks right, and in 20 years of production nobody has noticed their "Company Purple" is half a percent off in Rec.709 space. Outside of film and TV, corporate top brass don't have calibrated monitors!

..and I also use Resolve and Fusion for everything color-critical. They don't pretend to have fancy-schwancy swatch libraries but they can be trusted to keep colors accurate when you're given a bunch of weird footage, and they do ACES properly. After Effects has its uses (e.g. updating hundreds of text clips for video translations is a nightmare with Fu, wheras in AE you can one-click import from a spreadsheet) but you are correct about wasted opportunities. All the attention goes into stuff like "team projects", which is fat use if the colors are borked.

bontempos  wrote I know color spaces can be messy, but is it so complex even Adobe developers can't deal with it between their own applications?

Basically, yes. The developers of each app do their own thing, and in some cases have no contact with the other teams beyond installing the apps after launch. ACPs are actually a useful conduit here because we're often in several beta programs, and can argue for more uniformity. Although it's slowly improving, the codebase of each app remains neck-deep in legacy code and home-brew features, so it's not simply a case of copy-pasting a C function from inDesign to After Effects.

As I said earlier, CC Libraries came from the print people. They gave it features they wanted. The code that generates the panel was bundled into the other Creative Cloud apps, but whether or not those apps could use it was left to each team. For AE, that pretty much means we're at the stage of a "hello world" example.

The fact in 2019 we still have to tell people to switch to the operating system picker in order to save a custom swatch value is just insane, but it reveals the underlying issue - that for many time-served video app developers color is only ever something you adjust by eye, or with scopes. If if looks OK, it is OK. Whether it's C0C0C0 or C1C1C1 is completely meaningless to their way of working. They never export in CMYK or spot, so if a file in that color space doesn't display, or doesn't even import, they just tell the ink-stained print designer who sent them the file to go away and "fix" it. It's not just an Adobe attitude - Resolve has no swatch library, and FCP users have been complaining about color picker problems for years.

Of course this should be a golden opportunity for third parties to sell "swatch gallery" type plugins - it's perfectly possible to write one with the features exposed via AE's SDK - and the fact it hasn't happened suggests that most people using After Effects either think the same about color as those developers, or have gotten used to it being awful and work around it. Either way it means there's no pressure on Adobe to change the status quo.

Any color picker in AE can pick a color in the color swatches library. There is nothing to it.

Actually, there does seem to be something wrong with CC Library Swatches in After Effects. While you can use the eyedropper to select a swatch from the library panel, the values from the eyedropper are incorrect. For example, a red swatch in the Library which on hover reads #ff4365 / R255 G70 B53 color picks at a completely different value of #EB5542 / R235 G85 B66.