Obviously the map could be improved but typically it makes little difference for understanding what it is that is shown when it is seen in isolation.
When this map is part of a continuum of maps, it will show the movements over time. It will show where they are at a given time. They will show where the Vandals settled down and show where they fought their battles. Better understanding will emerge but it may get complicated. The Vandals were not the only ones around. It was a time of turmoil and only when the shape of former countries and battles are shown a better understanding emerges.
For many "former countries" maps are not available and when they are they are of a similar quality as the map of the Vandals. What I would love is maps as an overlay and just add maps and facts as they are available. Many maps will only over time get some credibility but it is an improvement over nothing to see.