Swiss law upholds the principle of freedom of contract. Basically, what this means is that a contract can be formed solely on the basis of an informal mutual declaration of intent by both parties. Everything else is then «simply» a matter of provability in the event of a dispute. Freedom of form means that a contract, in order to be valid, must meet particular formal requirements only if expressly stated by the law or contractually agreed by the parties. Such formalities are only required for the legal formation and not, however, for the legal (continued) existence of a contract.
Contracts do not lose their validity therefore on scanning and subsequently destroying the original, as they are already valid at the time of scanning (insofar as the relevant formal requirements have been met).
However, we would like to point out that in some cases it may be worth retaining an original copy of an important contract for the purpose of substantiation. In extreme cases, a opposing could claim that the signature on the scanned and subsequently printed contract is not yours. As a PEAX user, this is your decision to make.
We do, however, recommend scanning all contract-related documents (e.g. letters, emails, etc. relating to before or after the conclusion of the contract), too. In the event of a dispute, the opposing party thus has no chance of claiming that you did not sign the contract yourself or that your signature is forged.
We also recommend retaining original copies of particularly important contracts or those which involve a return service by the opposing party being rendered in full or in part at a later date and potentially being disputed. For example: a loan agreement (as lender), a promissory letter and other service commitments (as creditor), guarantees and warranties, employment contract and employment contract termination, job references, school and training certificates and diplomas, official documents (a copy of which is also held by a notary), a holographic will (a mere copy of which would be invalid, i.e. the original must be retained!).