Explanation: Oftentimes, Rome would ‘subsidize’ vassal states on the frontier. In early periods it was actually very effective. Roman ‘subsidies’ to their client states reinforced the power of pro-Roman elites and improved the capabilities of the clients to repel their neighbors - which was usually their primary purpose, as buffer states.

... but by the Late Empire, when the barbarian tribes were more desperate to get into the Roman Empire to escape enemy tribes and climate change, not just seeking loot and glory; and when the Empire's own military forces had degraded, especially in comparison to the barbarian tribes, it was... probably quite counterproductive.

The GDP (gross praetorian product) was way up though.

Who's the madlad on the right who's flying a Chinese dragon puppet?

That's a draco standard, a practice the Romans adopted from the Scythians! The draco was a kind of windsock/whistle which made an eerie noise when wind passed through it. They were most often used in cavalry units (because on the charge it will absolutely be getting enough air to make noise) because horses who aren't accustomed to the sound tend to get jittery, which is useful when attacking other cavalry.