Encrypting and decrypting with AES returns System.Byte[] [duplicate]

Using AES in C# I wrote two static methods for encryption and decryption.

Encrypt:

static byte[] Encrypt(byte[] plaintext, byte[] Key, byte[] IV)
{
    byte[] encrypted_data = null;
    using (Aes aesAlg = Aes.Create())
    {
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        ICryptoTransform encryptor = aesAlg.CreateEncryptor(aesAlg.Key, aesAlg.IV);

        using (MemoryStream msEncrypt = new MemoryStream())
        {
            using (CryptoStream csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
            {
                using (StreamWriter swEncrypt = new StreamWriter(csEncrypt))
                {
                    swEncrypt.Write(plaintext);
                }
            }
            encrypted_data = msEncrypt.ToArray();
        }
    }
    return encrypted_data;
}

Decrypt:

static string Decrypt(byte[] encrypted_text, byte[] Key, byte[] IV)
{
    string decrypted_data = null;
    using (Aes aesAlg = Aes.Create())
    {
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

        using (MemoryStream msDecrypt = new MemoryStream(encrypted_text))
        {
            using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
            {
                using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                {
                    decrypted_data = srDecrypt.ReadToEnd();
                    return decrypted_data;
                }
            }
        }
    }
}

static void Main(string[] args)
{
    byte[] Key = GenerateRandomKey(32);
    byte[] IV = GenerateRandomIV(16);
    byte[] data_to_encrypt = Encoding.UTF8.GetBytes("Hola como estas");
    byte[] encrypted_data = Encrypt(data_to_encrypt, Key, IV);
    File.WriteAllBytes("encrypted.enc", encrypted_data);
    byte[] data_to_decrypt = File.ReadAllBytes("encrypted.enc");
    string decrypted_data = Decrypt(data_to_decrypt, Key, IV);
    Console.WriteLine(decrypted_data);
}

I use them in Main() where I generate a random 256-bit key and an IV of 128. I get the bytes of the string I want to encrypt and use the function to encrypt them, then write them to a file and read them again to decrypt but when trying to display them in the console it only shows the type "System.Byte[]".

Why does this happen instead of showing the decrypted data string?