I was curious what the protein picture was showing: "Figure 1 Example predictions of SimpleFold on targets ... with ground truth shown in light aqua and prediction in deep teal."

and now I'm even more curious why they thought "light aqua" vs "deep teal" would be a good choice

Well, figure a) shows a ribbon representation of the fold (as helices and strands) of the protein 7QSW (https://www.ebi.ac.uk/pdbe/entry/pdb/7qsw) which is RubisCO (https://en.wikipedia.org/wiki/RuBisCO), an plant protein that plays a key role in photosynthesis.

The different colours are for the predicted and 'real' (ground truth) models. The fact that it is hard to distinguish is partly the - as you point out - weird colour choice, but also because they are so close together. An inaccurate prediction would have parts that stand out more as they would not align well in 3D space.