I run across that every once in a while when I'm trying to find a paint that was discontinued in some Citadel rebranding or other, or just trying to find something cheaper than GW.
I run across two real issues. Firstly, the table can be a bit misleading, as people will sometimes look at it thinking that they can match one paint by grabbing its equivalents from the table. This isn't always the case. Trust me, NOTHING quite matches Shadow Grey. Secondly, the table only lists dedicated mini and model paints. It'd be far more useful if it also allowed you to look up equivalents from craft paint lines, like Apple Barrel or Delta.