Is there any benefit to being Master / Legendary in a Save?

[MuddyVolcano]

...aside from a higher bonus? I'm looking, but haven't found this yet.

[Wolfism]

There doesn't seem to be much more to it right now. It may be that they plan for feats down the line that are unlocked by it but I haven't seen any yet.

I just posted a similar issue about weapon and casting proficiency and a possible solution to it.

[willuwontu]

By RAW no, however most of the features that grant master in a save also grant the ability to treat successes as critical successes. This should become baseline for master proficiency IMO, along with legendary proficiency as a baseline causing crit fails to be fails instead.