Buy the car for yourself, not for the next customer.
If it is in good condition, it will sell. My friend's honda city was in orange color, and people used to mention that it's not a popular color. After 4-5 yrs and over 100,000 kms, when he put it up for sale, the offers were fine and quick. He ended up selling to his father but he told me there was no problem selling it based on the number of people who visited and number of offers made.
Corolla is a hot re-seller, having an unpopular color means if white sells the same day, charcoal should sell in like 4-5 days. Few weeks back I saw a charcoal 2019 Altis 1.8 CVT (non-Grande) and the demand was either 37 or 39 (I don't remember the exact, but it was more than the price of the new car). I talked to the dealer he said it's the going market rate.
So don't worry about the next customer, buy for yourself.
One drawback is that if your car needs a touch-up, matching the color will be difficult. Second, its a darker color, so under the sun it'll get hotter than white. But these are very minor things, specially the 2nd one. So if you like the color, go for it.
