He knew that Treyton immediately understood that it could also be helpful for them.
They could use it to detect where their comrades are, as long as they weren't too far away.
So, he immediately said that he could teach it to Nichole because he doesn't want to do monitoring himself.
"Yes, thanks. But Ciel, you should also give one to me," Treyton said.
"Why do you even want to have one?"
Treyton could obviously survive on his own even if he was separated from others, so he doesn't need it.
He was only giving it to the three kids because it would be harder for them to survive if they were separated by chance.
If that happened, then he could at least look for them immediately if they happened to be in his monitoring range.
He was a bit fond of them, so he could at least spare the effort to look for them if it really happened.