I use soul matching every now and then to "upgrade" some of my favoured pieces to higher levels. Sometimes I'll use a really nice light piece of armour, and all the newer pieces are heavier and barely have better defense (sometimes, not even) and/or less cool attributes, so to make my, say, nice level 50 light armour better I'll soul match it to a level 60 piece I just found and pump its defense a bit more.
Do the same with my dual kats. I rarely find really good dual kats, right now I'm using a fire one that's really nice, and the higher level ones I find are all yellow with 1 or 2 mediocre attributes, so I soulmatch my fire kats to them to buff them up.
It's not too expensive if you do it like that. But yeah if you want to soul match the Warrior of the West bow, LOL. Not worth it especially since bow damage isn't that useful, just gotta go for headshots.