Marco Of course you can use cash if you want, but if you do: bunq is unfortunately not the right bank for this. You can use bunq for all your online payments and card payments, and a few cash payments every month, but if you're planning on using a lot of cash payments, I recommend also having an account at a different bank.
Cash is 'dirtier' than digital money, exactly for the reason you mention: anonymity. There's no way to trace a cash payment, so that's why criminals like to use it. And that's also why banks don't like cash payments, because if they want to investigate fraud, cash payments don't help.