What is the rationale for prohibiting proxy fulfillment of the Rosh Hashanah prayer specifically?

Synopsis

Prayer (teshuva) is a personal devotional act requiring individual intention and internal request for mercy, which cannot be substituted by a proxy regardless of the proxy's qualifications.

Late Acharonim
Lenient
Strict
Lesser cited
Major authority

Discussion

Discussion coming soon.

The Daily Law

One question. Every opinion. Every morning.

A new halakhic question and the full spectrum of rabbinic thought, delivered daily.