I had a lobster from this genus through part of last year. There are two problems really.
1. If you want to see them, you can't give them anywhere to hide completely or form a deep burrow. This stresses them and is not a good way to go for the wellbeing of the animal.
2. To not stress them, they need a way to hide completely. They don't want to see you, and they don't want you to see them. As a result, you may literally never see them, even at night. They'll detect the vibrations coming and hide again even in the dark. All it takes is a tiny vibration they don't expect to send them shooting back into their burrow sometimes. This makes it really hard to determine whether they are doing ok or not.
Mine molted many times for me and grew a bit, the only evidence I saw being the old skins for the most part. Every now and then I'd be a pain and lift up the cave it lived in to make sure there was still a live animal there. Then, one day after quite a few months, it was a dead animal. I have no idea what led to the death - could have been natural or that I messed something up, but I have no idea. The uncertainty there has left me hesitant to ever try another one, since I like to be able to look over all my animals regularly to check for injuries, odd behaviors, and other symptoms of things that need attention. Can't really do that with these animals.