I just completed 3+ weeks Gibraltar to Andorra tour with Panaracer Gravel King 38mm slicks sealed with Silca sealant. Did hundreds of km of gravel. Had one substantial leak near the end which would weep but essentially slowed the leak to insignificant. Plugged with Dynaplug and it’s still in the tire, problem solved. Using tubeless for tour means I can ride a supple lighter weight tire which is much more pleasant to ride especially for those off days when unloaded just exploring a new place. There is no real downside for running tubeless.