Is sand always bad?

I’m a bit of a noob with geckos. They get sick if they eat too much sand but if I just feed meleworms to him in a dish sprinkled with calcium would he still be at risk from the sand somehow? I have a carpet down now, not crazy about the look. Aside from that I feel like he’d have more fun burrowing in the sand but I don’t know if he’d still be tempted to eat it for some reason lol.