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In my (unpublished) [code changes](https://github.com/brakmic/bitcoin/commit/0b3ee615491edf6f542631bf6ae6f72eac406550) all raw pointers got replaced with **shared_ptr**s but kept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,
bool can_avoid_reuse = pwallet->IsWalletFlagSet(WALLET_FLAG_AVOID_REUSE);
    bool avoid_reuse = param.isNull() ? can_avoid_reuse : param.get_bool();
    if (avoid_reuse && !can_avoid_reuse) {
        throw JSONRPCError(RPC_WALLET_ERROR, "wallet does not have the \"avoid reuse\" feature enabled");
    }
    return avoid_reuse;
}
/** Used by RPC commands that have an include_watchonly parameter.
 *  We default to true for watchonly wallets if include_watchonly isn't
 *  explicitly set.
 */
static bool ParseIncludeWatchonly(const UniValue& include_watchonly, const CWallet& pwallet)
{
    if (include_watchonly.isNull()) {
        
        return pwallet.IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS);
    }
    
    return include_watchonly.get_bool();
}
bool HaveKey(const SigningProvider& wallet, const CKey& key)
{
    CKey key2;
    key2.Set(key.begin(), key.end(), !key.IsCompressed());
    return wallet.HaveKey(key.GetPubKey().GetID()) || wallet.HaveKey(key2.GetPubKey().GetID());
}
bool GetWalletNameFromJSONRPCRequest(const JSONRPCRequest& request, std::string& wallet_name)