Round here there are various traces of Roman occupation. Not too far away there are hut circles and also a rectangular Romano-British ruin, so someone around 2000 years ago was copying the new style of building. From visiting Caerleon, it's obvious that the Roman conquerors intermingled with the natives, at least in the South of Wales and the border, intermarrying and retiring to live nearby rather than returning to Rome or wherever it was in the Empire they came from originally.
Of course the Romans plundered the territories they conquered. They mined gold further south at Dolauchothi and though I don't think there's any evidence of it and I've never seen it mentioned in the histories I've read, I suspect that they would have mined gold and copper here too. Why else would there have been such a heavy military presence at Trawsfynydd? Any traces of Roman mining would have been obliterated by later mine working because they were quite rich seams.
But having said that, I find it so poignant when little personal items survive from any culture. Things like the bits of jewellery that were dug out of the drains at the Roman Baths in Caerleon, the horde of silver coins that someone had buried and never went back to reclaim and the details of the soldiers funeral arrangements. I suppose I feel about the Romans much as I do about any aggressive, world dominating political system. I don't like their policies or some aspects of the culture, but I feel a lot of empathy for the individual citizens.