SimC gives you the buff 100% of the time on a patchwerk fight. We do have some movement in the script we use to rank the trait, so it won’t be up all the time. You should be able to achieve very high uptime on it if you avoid unnecessary movement. I realize that can be hard/annoying for some players, but we rank the traits on their potential power.
If you don’t want to use it, lock in your preferred trait, or use the “customize” feature to nudge the optimizer towards your preferred build.