If you want to portray a professional image then in my opinion you need to dress the part.
However if it’s just a statement of “look at me I’m a pilot” then that’s self feeding of one’s ego. A private flight, flying your mates - no..
In the circumstances you describe it would seem that a uniform would add to a client’s perception of quality and value of the service. Do you see an Airline’s pilot dressed in Jeans and T-Shirt? What would you think if he/she did?
I’m surprised that you need to ask the question...