There isn't a huge difference between interlace component output and RGB. progressive component is obviously better but if your talking about interlace there isn't much in it.
RGB is actually what feeds the guns of the tube so you can't really get any more pure a signal.
for a television to produce a picture from a component input it has to take the luminance and sync from the green connection. Then add this luminance to both the red and blue connections before this signal is then sent to the tube guns once amplified. The field sync is a seperate connection. Where as a scart rgb signal is just amplified and sent onto the tube. The trouble with RGB is your more likely to get a mismatch of signal levels and other problems but a well configured interlace RGB connection is equal if not better to a component interlace connection.
Points to note;
Some tvs don't actually have a true RGB mode they downgrade it internally to s-video then process back to RGB later on for the final stage to the tube.
Component is more tightly controlled with regards signal levels and is less prone to compatibility problems.
Component is a feature of top end tvs that are more likely to have a good picture anyway.
The specification of Scart RGB actually exceeds component in bandwidth for colour and resolution. RGB is no different to VGA except it uses only one sync connection and is a lower resolution interlace tv compatible mode
DVDs are stored in component form.
Component is more effective for long cable runs.
Anyway the end result is either connection can be better depending on equipment.
I would have thought Arcam would have done a nicely fine tuned scart RGB output. They tend to perfect every little circuit in their players.
Perhaps Sony like Philips think component is a pointless addition when you have scart RGB.