I think it is definitely worth a shot.

A good therapist should be able and willing to work with the fact you are not yet comfortable enough to use your (verbal) words, and I think a good therapist will help you get from the point of writing things down on paper to verbalizing what you want to say, AND get you to the point where you feel like what you DO verbalize is not "non-intelligible gibberish", but is meaningful and purposeful, as it really is.

I am not yet in therapy (getting myself to that point), but often feel like it would be so much easier to express my feelings/thoughts in writing (as I do mostly now... just happens to be the way it is), as when I am very anxious, my mind often goes blank and I can't think of "intelligent" way to put things (I just think they are not "intelligent"... but in reality, they are probably fine).

I good suggestion (for both of us!) might be to write topics/information down that we want to tell our therapists and bring those notes to our sessions, so that we will have our feelings/thoughts "in hand".

I, personally, probably wouldn't go this route, but have read on these forums that others have.... what about an online therapist or communicating via email?