The lack of Sony e-mount lenses. I wouldn't dare shoot a wedding with a 20 year old manual focus lens even if it does have great image quality.
Also: good luck having time to effectively manual focus in a fast paced situation as accurately as an autofocus lens.
You do realize people used MF lenses at weddings for
decades right? I know a few very talented shooters who still work with MF lenses at wedding. If you know how to shoot with MF lenses then it's not an issue. I actually shoot all of my fast primes with manual focus because it's quick and easy; and it beats being forced to compose a scene around my focus points. A good focus screen makes manually focusing fast glass very easy, slow consumer zooms, not so much. However, have you ever worked with focus peaking? It's great, and makes manual focus fast and fool proof.
Yes I do know this. However, there is a reason why autofocus is seen as important to a lot of photographic community.
I know many photographers who don't use manual focus because almost every AF point is cross type and they just have to click over to a new one when they need a new composition.
My cameras don't have focus peaking. My Fujifilm does but it's a hybrid and is often very distracting.
I would not buy into a system that lacks a native lens system just so I could make concessions using manual focus third party lenses.
That is where I'm coming from. You can always turn of AF on Sonanonikon lenses, but you can't add autofocus to a manual focus lens.
However, if you're skilled at manual focus do your thing. I don't have a place to criticize your personal way method of taking photos.