In start ups, I have seen candidates nearly rejected just on a suit alone. Def started them on the wrong foot impression wise.
'Uniforms' can go both ways. Would a person who only owns white Oxford shirts and monochrome dress pants have to go out and buy a new wardrobe he would feel very uncomfortable in if he wanted to work there? People who wear 20 year old band t-shirts can be every bit as judgemental about looks as people who wear tailored Italian suits.
Hipster/lumberjack can also work. Make sure the jeans are $400 Japanese raw selvedge to really get it right.
The highest ranking person I ever shook hands with was the GP Morgan head of futures department. He came to talk to the whole company to prep for acquisition. So, it wasn't a super official "ceremony", but it was in front of some fifty men, including senior management of the said company. He was wearing a polo shirt, jeans and a pair of sneakers. I don't know if this is how he'd show up to his office in the bank. Likely not (but who knows?)
Also, nobody in that room was wearing a suit.
Maybe your advise works for other places. For vast majority of programming jobs showing up overdressed will raise more questions about your sanity than score any points on preparedness.
He was wearing some sort of jeans and polo shirt combination (the same as the other executives) and it looked terrible to me (the proportions were wrong, the jeans were too long--he looked like a clown) and I thought his attire was disrespectful. The people there, who cared about looking presentable given the importance of the event for the 200-person satellite office, looked much better than the power-ups.
In my opinion, this doesn't show that he only cares about the work and not silly, old-fashioned dress codes, but that he's too good for us to take the time to look good.
In case you mean JP Morgan, here's the CEO, Jamie Dimon, on cover of annual shareholder letter, back in ... 2015:
https://finance.yahoo.com/news/jamie-dimons-style-telling-jp...
I recommend a t-shirt with a tuxedo design printed on the front. The very definition of smart casual.
