Yup
But it’s the easiest/safest delivery mechanism and you can make things easier to copy and paste, or automate a little better, and provide full instructions with images on how to redeem keys.
Then you just whisper the user to visit the site and claim their key in their own time. And you can also see which keys have not been claimed from your system if you put an arbitary time limit on the claim.
Additionally you can then put a Captcha on it, to prevent chat bots claiming prizes from chat. Meaning you deliver more prizes to legitimate winners.
Edit: you could also look at using an extension instead. I built such an extension for someone and it worked really well for key delivery