Competitive Skirmish in Bannerlord is far less interesting to watch than Competitive Battle from Warband.
Fewers maps, fewer players on a team mean the fights feel fairly predetermined from the outset, with strategy being pretty standardized across the board.
Faction matchups don't really cause much variation in tactic changes, some factions which do prompt composition changes are usually in response to an overwhelming weakness from one class in that faction, which simply causes that faction to lose (most of the time).
It's frustrating to watch a top-down camera angle as it feels like the players have no cav awareness (which is still limited by the sound bug).
Fights begin quickly and end quickly and it becomes uninteresting to watch the spawn cycles of one side being wiped then coming back/wiping enemy team/repeat. There is no tension akin to how a one-life mode appears to a viewer.
Flags are an annoyance to both the players and the viewer. Flags are intended to force fights, but ironically if they are played as a strategy it incentivizes cavalry players to avoid action (and therefore the inf players not to take a fight), and the game becomes a cat and mouse of two teams making a circuit around the map running away from each other.
Spawns are also so random on some maps they cause games to be won or lost depending on spawn proximity to the fights, which would surely be confusing and frustrating to a viewer.