C#

public struct DecimalDigit
{
  public static readonly DecimalDigit D0 = new(0);
  public static readonly DecimalDigit D1 = new(1);
  public static readonly DecimalDigit D2 = new(2);
  public static readonly DecimalDigit D3 = new(3);
  public static readonly DecimalDigit D4 = new(4);
  public static readonly DecimalDigit D5 = new(5);
  public static readonly DecimalDigit D6 = new(6);
  public static readonly DecimalDigit D7 = new(7);
  public static readonly DecimalDigit D8 = new(8);
  public static readonly DecimalDigit D9 = new(9);

  private DecimalDigit(byte value)
  {
    _value = value;
  }

  private readonly byte _value;
  public byte ByteValue
  {
    get => _value;
  }
}

// vs

public enum DecimalDigit:
  byte
{
  D0,
  D1,
  D2,
  D3,
  D4,
  D5,
  D6,
  D7,
  D8,
  D9
}