Very interesting question with very interesting answers. For me, the answer is yes.
It partly depends on the sort of instrument you play.
When playing a keyboard instrument, you may already be familiar with chords and the balance between melody and accompaniment.
When playing a ''one-voice''-instrument, you may have less experience with these aspects of composing.
As a saxophonist I notice that for me composing melodies is way more easier than creating stable harmony following the melody.
Before I began composing, I was already able to read simple music notation. Without the ability to read scores, it would be immens hard to compose.
I think it is worth too to discuss the following:
Has your composing ever benefitted playing an instrument?
The technical aspects of playing saxophone have, in my case, not been improved by compositions.
Embouchure, finger velocity etc. do not improve by composing.
However, I notice that my music theory (for instance Italian terms) and music interpretation (such as frasing) do improve by composing. The primary benefit is the latter, which helps me to understand how the music has to sound and what the composer wants to express with his creation.