If they are almost identical for NDL, then I think criticisms seem irrelevant. BSAC uses a different definition of bottom time too, so that is something to keep in mind when you look at the BSAC tables.
For decompression there are differences, and I have heard (but not verified) that BSAC tables are more aggressive. What real life implications this has had (if any), I have no idea.
Also I don't think it is correct to assume that the BSAC tables were improvised, just because they have not revealed how they have been calculated. It might have been but you don't know