If it's a good idea or not is up to you. And the success of the strategy depends on what your actual goal is.
No Time to Explain did this way back in 2011. They uploaded a special version of the game to Pirate Bay that had all the characters wearing pirate hats.
“We thought it’d be funny to leak a pirate version ourselves which is
literally all about pirates and pirate hats,” Alex told TorrentFreak.
“I mean, some people are going to torrent it either way, we might as
well make something funny out of it.”
It's unknown if the strategy of creating a special version just for pirates gets more pirates to buy the game instead of pirate it. However, it's been shown in the past to improve the media coverage of the game, potentially drawing more legitimate users. The developers of No Time to Explain said:
“We saw very positive WTF REALLY feedback from users, and saw
reactions that people bought it simply because they liked the joke. So
we don’t see it hurting sales in any way,” Alex said.
However, it's unclear if this strategy only works for games that were already popular, or if a fairly unknown game could be boosted into the spotlight with this method. Further, this strategy likely has limited uses. It's only been successful because it's somewhat unique and interesting. If every game does this, it's not as interesting and news sites stop reporting on it.
You could opt for a more subtle approach of just including a message for everyone, telling them you've worked hard on the game and you appreciate their purchase of the game. Something like what S.P.A.Z. did:
There are a number of approaches to marketing and getting your game more widely known. There isn't any evidence (as far as I know) of any strategies that effectively convert pirates into paying customers. So, if your intention of doing this is for marketing, then sure, it's worth a try, but if it's solely an attempt to convert pirates, you're not likely to have much success.