The only time I trim raveling threads from the back of a quilt top is if the threads are underneath a light or muslin fabric where they might show. Usually if my light fabrics are good quality, even this is not necessary as once the quilt top is layered on the batting the underneath threads no longer show.
Are you pre-washing your fabric? If so, do you starch before cutting? I'm wondering because I do not pre-wash fabrics and I usually don't have a lot of ravelling anyway. (Except my current 30's repro fabrics fabric, which seems to ravel a lot.)
Those who use the pinking blade usually use it on the edges of fabric before washing, to cut down on ravelling from pre-washing. Some sellers of jelly rolls pink the edges to prevent ravelling. However, I don't know of any home quilters who use a pinking blade to cut out pieces for blocks. I think you would lose too much in accuracy.