there are a lot of tools for clarifying your thinking process while trying to write software. Flowcharts are one of them. If it helps, great!
Personally, I don't find a flowchart particularly easier to read than the average high level language program, perhaps because most of the problems I've faced don't fall apart into nice decision trees. (hmm. The yenka web pages are rather vague on just what sort of flow chart elements are supported.)
I think flowchart started to be less useful when it became clear that defining good data structures was as important as defining code flow (that is, when fortran and basic became 'BAD' languages.) Hmm. Data structures. Not something that gets mentioned much in arduinoland, though a fair amount of thought goes there in defining the library classes and such.