Many are owed to traditions. Game end rules have not been spared. Comparison Simple area rules, agreement area rules, and territory rule sets shall be compared. Agreement area rules often allow a short confirmation of removals, but their texts are longer, the game structure is complicated by stop and confirmation phases, and with the players' disagreement the extra moves for removals are also needed. Possible agreements in most cases are a compromise for all who want to avoid the elegance of simple area rules.
People preferring agreements argue removal moves blot the position.
So they keep blotting it with hypothetical play instead and are afraid of being forced to use a minute for a game end in alternation. Area rules are concise, simple, and logical. The only disadvantage is that more points are counted. Territory rules are long, complex, and illogical. The arguments clearly favour area rules.