I bought a Lily two weeks ago and have used it for several walks. I have not gotten an accurate distance yet. For the first walk, I used the Connect app for the GPS connection. For the second, I attempted to use just the watch (so measuring step distance). Both walks were routes I walk regularly, and my partner’s Garmin (I forget which model, but it has built in GPS) accurately recorded the distance for both walks.
For reference, my watch is on the SW Version 4.60.