Why do lawyers keep documents in tangible form?

A computer (and the data in it) is dependent on electricity. Unless you have power, that data is totally inaccessible. You make think that power is something that will always be there but imagine a disaster like the earthquake in China or the tornadoes in the mid-West. All power gone and someone needs a lawyer (and his data) urgently. The other (and perhaps more valid) reason is that legal documents very often need an actual signature. A photocopy or a scan is not good enough because it's too easy to tamper with a document that way. Computers are useful tools for processing data. They are not really the best or most secure way of storing or archiving data long-term.

Many legal documents are required to be an original with the original signatures. If the document has to be notarized, in many states, it is required that a embossed seal be applied, which can only be done with the original document.