A counter is only part of the workflow
An app can replace tally marks or a clicker for a running count. For pattern work, it helps if the app also gives you a place to record the row or round, expected stitch count, and a note about the next repeat. Otherwise, you may remember the number but lose why you were counting it.
What SkeinHub currently supports
SkeinHub keeps a counter and project progress in the same workspace as a pattern and notes. It supports row and round project modes, plus step and repeat controls in the counter. That makes it useful for tracking a stitch count while working, but it is not a stitch-diagram recognition tool and it does not check your physical stitches automatically.
See the crochet row counter feature and the guide to counting stitches without losing your place.
A simple test before you commit
Count ten stitches, leave the app, reopen it, and check that the value is still attached to the intended project. Then try an undo and a manual correction. These small checks reveal whether the app fits your actual making routine.