Found that to be totally true when I was trying to transplant some overgrown lavender last year. The narrow blade on a spade cuts through roots way cleaner than my regular shovel. I could actually feel where the big roots were and work around them without hacking everything to pieces. It just gives you more precision, like using a chef's knife instead of a cleaver. Ended up saving most of the plant because I wasn't just tearing through the dirt blind.