Because it's SC checker, not DW
But when you learn first what errors are "legal" i.e. showed even on original DW doctrines (new keywords for example) then checker is VERY!!!! helpfull in finding new ones !! I usually check how many errors were before modifications and after, if number is the same then usually OK

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If my doctrine shows more errors, then I check if those are real errors or caused by checker/DW incompatibility. In 99% of cases it turns out to be my error (something unbalanced, no space, ect.). Couldn't work without this tool

I hope jsteed will relase DW version.