LEDison emulation was an advertised feature, but doesn't appear to work at all, or properly currently. The option is in the cosmo settings menu.
I use it the LED's every day on my Gemini to, at a distance, see which of my three mailboxes (red, green, blue) gets new e-mail. My only problem with them on the Gemini is that they're kind on sloppily implemented. They're supposed to handle 24-bit RGB, but each channel can, in reality, essentially only be full on, maybe a wee tad dimmer or completely off. And the timing isn't very tight. I fully intend and expect to use their emulated counterpart on my Cosmo, whenever it may arrive.
For my needs, just being able to have the whole OLED panel light up in one color might be enough, but since the 5-LED strip has already set the precedent, I don't see why it shouldn't be implemented. Especially with the outer display in the advertised landscape mode, drawing five filled circles (boxes would do) should be very doable.