You don't want a mistrimmed aircraft in already challenging wind conditions on short final.
The 737 AFDS flies the approach like sh*te and will happilly go into the red speed areas and exceed stabilized approach criteria when the winds starts to get a little gusty, I know this by experience, hence the need to fly it manually if you don't want to divert or be summoned up to the office for tea and biscuits explaining the the nice exerpts.