I own and run a web development business and not unlike other types of businesses – what you wear when meeting with clients is important and sends a message about who you are.
When getting ready to meet my clients in person – I can still hear my mother in the back of my head “wear something nice, look professional” (not that she ever told me that – but I imagine she would if I still lived with her). Perhaps older generations do not understand is that the tech business is much different than others.
If someone in my position came to meet with me in a business suit – most people might think “wow this person is really professional and put together.”
As a tech person – if I see this same person dressed in a suit – I think “wow – this person is trying to sell me something vs. knows how to solve my technical problem.” I do not think less or more of them – I just get a different message. I feel that people in our business who are comfortable with their skills and themselves will dress more casually and not “hide behind” a suit.
I am not saying you should show up in a t-shirt and sweat pants – nor do I think you should never wear a suitto a meeting. I would just make sure you are comfortable with what you bring to the table and make sure you represent yourself in a way you are proud of/comfortable with and own it.
While I agree that what you wear sends a message – the message can differ and be interpreted differently by people. For fun, next time you have a tech person come in for a meeting – just take note of their dress and see if it correlates with the thought above (selling something vs solving something). I think most of the time you will agree with my statements above.