I, too, find it rather puzzling that Soames is a lover of novels, art and beauty in general.

All the Forsytes seem to be very materialistic people. They only care for money and hardly about "the beautiful things of life".
Soames seems to fit into this family as he is not very open-minded and intellectual, but fixed on money.
It is rather odd that such a person enjoys novels. Weren't they considered rather frivolous and a waste of time?
I can somehow understand about his art collection. It's a good investion of money and it looks very valuable and is admired by everyone. Same about the beautiful land he buys and about Irene, of course.
Any thoughts?