Hello,
My understanding is that checks, and cracks or splits are not the same.
checks
A crack or split
a split developed from a check.

That checks should be prevented as much as possible is an issue relating to joinery and not aesthetics because they occur at the end grain and are not usually substantially in sight. Splits or cracks, which occur at the surface are more than anything something aesthetic and only rarely concern the structural integrity of a timber.

Don Wagstaff