Very much so. It's also encouraged by many to leave one in the enclosure 24/7. It might not be touched but at least the tortoise has a choice whether to use it or not.
Ditto everything Alma above has said. It's cheap to buy, so even if never touched it's not a big loss to your funds. Some tortoises like them new and some like the old ones, then some never seem to ever notice them even. Just nice to have as a backup plan for extra calcium if and when the tortoise feels the need.