While working on this PR https://github.com/bitcoin/bitcoin/pull/18570 I ran into a bit confusing situation where in one function a **CWallet reference** was expected while two others dealt with **CWallet pointers**. My initial reaction was: `let's harmonize them by making them references`. However, not being part of the PR itself I did't change anything and completed the PR first.

Now, after having analyzed the `rpcwallet.cpp` code I came to the conclusion that:

* converting them all into references is not the solution as they're originally **shared_ptr**s
* but also: there is no (visible) reason why every RPC function should begin like this:

```cpp
std::shared_ptr<CWallet> const pwallet = GetWalletForJSONRPCRequest(request);
const CWallet* const pwallet = wallet.get();
```

This clearly defeats the purpose of shared pointers for no obvious reason. *Maybe I am missing something?*

In my (unpublished) [code changes](https://github.com/brakmic/bitcoin/commit/0b3ee615491edf6f542631bf6ae6f72eac406550) all raw pointers got replaced with **shared_ptr**s but kept their original names (that is, *pwallet*). In the end, they're pointers too, so the most of the original code remained untouched.

However, some of the helper functions couldn't be changed because external code is accessing them and I didn't want to make this task "virulent". So I introduced new ("Ref") variants that expect **shared_ptr** parameters, namely: 

```cpp
void EnsureWalletRefIsUnlocked(const std::shared_ptr<CWallet>);
bool EnsureWalletRefIsAvailable(const std::shared_ptr<CWallet>, bool avoidException);
```

I have tested the code, with python and boost-tests, and could not find any errors. 
But before opening a PR I would like to open a discussion about this. 

Is there any reason to keep on working with raw pointers when every function call actually begins with *shared_ptr*s?

Regards,
FlatSigningProvider expand_keys;
        std::vector<CScript> scripts;
        if (!parsed_desc->Expand(0, keys, scripts, expand_keys)) {
            throw JSONRPCError(RPC_WALLET_ERROR, "Cannot expand descriptor. Probably because of hardened derivations without private keys provided");
        }
        parsed_desc->ExpandPrivate(0, keys, expand_keys);
        
        bool have_all_privkeys = !expand_keys.keys.empty();
        for (const auto& entry : expand_keys.origins) {
            const CKeyID& key_id = entry.first;
            CKey key;
            if (!expand_keys.GetKey(key_id, key)) {
                have_all_privkeys = false;
                break;
            }
        }
        
        if (!pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
           if (keys.keys.empty()) {
                throw JSONRPCError(RPC_WALLET_ERROR, "Cannot import descriptor without private keys to a wallet with private keys enabled");
           }
           if (!have_all_privkeys) {
               warnings.push_back("Not all private keys provided. Some wallet functionality may return unexpected errors");
           }
        }
        WalletDescriptor w_desc(std::move(parsed_desc), timestamp, range_start, range_end, next_index);
        
        auto existing_spk_manager = pwallet->GetDescriptorScriptPubKeyMan(w_desc);
        if (existing_spk_manager) {