仕上げには重宝してる

[thetazuo]

「マジで人手が足りなくてさ……なっつんも中学校通い始めてから捕まりづらくなるし……ま、口は悪いけど作業は正確だから、仕上げには重宝してるよ」

The speaker wanted a person nicknamed なっつん to help her finish her work.

Hi. What would be the function of the に? Is like “use なっつん usefully for the finish”? Like AをBに使う？

Thank you.

 

[Joschl]

The particle/postposition に in the construction above is used to stating the purpose of an action.
"[Someone=The speaker] wa [someone else=なっつん] o [shiage] ni wa chōhō shite iru."
'[The speaker] always uses [Nattsun] as a convenient tool for doing the finishing process.'
* The speaker is talking about Nattsun in a disparaging way. (see 口は悪いけど[...] above)

重宝(する)２[...] 便利なものとして常に使うこと。https://kotobank.jp/word/重宝-527647

に (格助詞)（３）目標・対象などを指定する。「読書―熱中する」「魚釣り―行く」「君―見せてやろうか」https://sakura-paris.org/dict/大辞林/prefix/に

 

[thetazuo]

Thank you. I see.