When you try to convince anyone about anything and even when you are just talking you are using persuasive techniques whether you like it or not. You are doing it in this comment :), are you doing anything wrong? Is it wrong to be better at it? Is it wrong to use it in benefit of others like Tonny Robbins or Milton?
There is 100% nothing wrong with being better in communication, I would recommend anyone to get into the subject, it's crucial in this world, at the end the people who lack social skills hurt themselves mentally... I was one of them.
We can lie to ourselves that we never try to convince anyone to do anything and we never argue for our ideas beliefs... we are doing it... right now :)
Have a good day my brother.