I have not used silk but I have used Invisifil which is a 90 wt polyester that behaves much like silk. I used a heavier weight poly in a prewound bobbin. Like Newbee and Sewingitalltogether, I used it FMQ. My use was in a longarm not domestic. It sinks right down into the fabric and tends to mimic the fabric color. Great thread to use for tight fills or where you will have loads of backtracking as the buildup is not as obvious. Can't think of any pitfalls, other than the price tag.