What did England have in Roman times? Why conquer this remote island? But did not conquer Scotland?

The Romans loved to conquer. At that time, Britain not only had a large population (compared with Rome, it was pitiful, but better than nothing), but it was a pity to be a slave, and there was still a lot of land that could be used as a manor. As for Scotland, because it is too poor, and because Scotland is located in a mountainous area (the essence of Scotland now belongs to Rome in those days), its use value is not high, and it is particularly difficult for Scots. So it is normal not to conquer Scotland (a bit like the Central Plains Dynasty was unwilling to develop the Mongolian Plateau in history).