Why does an implicit conversion to [byte] work, but when replacing byte by bool it no longer works?

I. e. the following works...

Add-Type -TypeDefinition @'
public readonly struct MyByte
{
    private readonly byte value;

    public MyByte( byte b ) => this.value = b;

    public static implicit operator byte( MyByte b ) => b.value;
    public static explicit operator MyByte( byte b ) => new MyByte( b );

    public override string ToString() => $"{value}";
}
'@

[byte] $d = [MyByte]::new( 1 )    # OK

...while this very similar code does not:

Add-Type -TypeDefinition @'
public readonly struct MyBool
{
    private readonly bool value;

    public MyBool( bool b ) => this.value = b;

    public static implicit operator bool( MyBool b ) => b.value;
    public static explicit operator MyBool( bool b ) => new MyBool( b );

    public override string ToString() => $"{value}";
}
'@

[bool] $b = [MyBool]::new( $true )    # Error

This produces the following error:

Cannot convert value "MyBool" to type "System.Boolean". Boolean parameters accept only Boolean values and numbers, such as $True, $False, 1 or 0.

Note that in C# the implicit conversion to bool works as expected:

public class MyBoolTest {
    public static void Test() {
        bool b = new MyBool( true );    // OK
    }
}

So this seems to be a PowerShell issue only.

(PSVersion: 7.2.2)