There is a point of view that the enforcement of Shinpei's policy succeeded to eradicate opium usage in Taiwan and put away those backdoor groups who had dealt with opium as an income source, although some also suggest that Shinpei himself gradually deepened his relationship with those backdoor groups and also the concessions related with opium involved Shigemaru SUGIYAMA and others as the partners.
これにより新平の施策実行から50年近くかけて、台湾はアヘンの根絶、アヘンを重要な資金源としていた黒社会の勢力を大きく後退させる事にしたという見方がある一方、これによって新平自身が、杉山茂丸らをパートナーとして阿片利権・裏社会との関わりを深めていったという見方も存在する。