I do not have any observable difference to the rCRS, can this test be accurate or useful?
Mitochondrial DNA (mtDNA) was first sequenced in 1981 by Frederick Sanger in Cambridge, England and subsequently revised and published as the revised Cambridge Reference Sequence (rCRS). A group under Dr. Sanger sequenced the mitochondrial genome of one individual of European descent. The rCRS has become the reference standard against which all mtDNA sequences are compared. Having no differences from the rCRS is just as useful as having multiple differences. If the CRS had been created using a person of African or Asian descent, then your observable differences would be different. Having no differences from the rCRS helps narrow down maternal lineages and haplogroups.
