There's an important thing to consider here -- what is actually being stored. Finger scan technologies do NOT store your fingerprint -- they store metadata. Sort of like a one-way hash, this information is gleaned FROM the fingerprint and the algorithm is not reversable. The data stored includes details about ridges and valleys, usually from a handful of points around the fingerprint. You cannot regenerate a fingerprint from the stored data.
Additionally, finger scans take much less storage -- only a few kilobytes. Complete fingerprint storage requires much more space.
The downside to using finger scans is that the FAR (false acceptance rate -- where Alice's finger is determined to actually be Bob's) and FRR (false rejection rate -- where Alice's finger is determined to not be hers) are higher.