Deep vigor usage

[Yonko]

Tooltip says it can be used only after chain 4. When does this skill actually become useful? I only ever get a max 4 attempts, am I missing something? lol

All unspoiled nodes start with 6 swings possible (well all the pre 2.4 ones can't speak for the newest) So its useful then through most of the time I'm going for quantity so I end up saving my GP and only doing 5 swings (at +2) (swing to reveal > +2 (500 gp) > +5% (50gp) swing x5).

The Deep vigor is very useful to get at least 1 HQ when going for the i70 tools.