I like the thought, but I don’t think it’s that simple.
More like tact is mindful honesty. The tactful statement may in fact be more honest than the brutally honest statement, because it has examined the raw feeling and mined some kind of actionable/constructive information from it.
That may be an obvious distinction for most, but as someone who struggles with tact, it’s been valuable for me to recognize that the most honest statement is one that’s been really thought through for context and impact.
Tact, for me, is the act of adding why and how to an honest feeling before expressing it.