I don't understand how a contract can be UN-enforce-able, but still valid? Doesn't "uN-enforce-able" mean "invalid"?
Presuppose that your surgeon doesn't email with patients, you formed an oral contract with the Dr perfectly, and you recorded it as a WAV audio file. Indubitably it's a valid contract, and evidenced electronically or digitally – but not in writing. But if the audio file is un-enforce-able, then your WAV file is useless!
As we have already seen in Chapter 1,1 the general principle is that contracts may be made entirely orally, no matter how valuable or important the subject matter of the contract may be. However, there are some exceptions to the general rule that no written formalities are required, and this chapter will examine two classes of contract. The first encompasses particular categories of contract which must be in writing as a result of legislation. The second concerns certain types of contract which are not enforceable unless evidenced in writing. It should be noted straight away that there are important differences between the two classes. As regards the first, the ‘contract’ will be void if not in writing. But as regards the second class of contract, any contract will be valid but simply unenforceable if not evidenced in writing. This means that, where a contract is made orally, neither party can sue on it unless and until a party can produce the appropriate written evidence of it. Such evidence may come into existence after the contract has been made.
JC Smith's The Law of Contract 2021 3 ed, p 115.