Its like they didn't know how to fill-out the gab above the ANSI enter key and just put a random symbol which nobody uses frequently and made the key bigger for no reason whatsoever apart from being big enough to fill out the gap.
That’s the design philosophy for pretty much everything on any standard-layout keyboard. Blame IBM.
The enter key was originally designed the way is it on the ISO layout,
The earliest enter keys are circular, found on typewriters. After that they come in all sorts of shapes and sizes. There isn’t really any “original design” going on.
For my taste, the ISO design is extremely uncomfortable to type on using any quasi-standard typing technique with the right hand home position on JKL; because it requires reaching the pinky finger 3 keys over to the right. Between that and the extra reach for left shift, I find ISO substantially less pleasant than ANSI, but both are pretty bad. The backslash, +/- keys, right bracket, backspace, right shift, backtick, control keys, and numbers 5–7 are all uncomfortably long stretches. With just a tiny bit of key rearrangement it’s easy to make a substantially friendlier layout than ANSI/ISO/JIS.
But that's just how Americans are, and always where, they don't give a ****, and as long as the USA refuses to accept the standard ISO layout, along with the metrical system and so many other things, you will have to deal with it.
For what it’s worth, all the standard keyboard layouts are ****. But many of the problems constraining keyboard designs in arbitrary and suboptimal ways come from German standards from the 80s, which basically doomed the wonderful tall keyboards of the 70s, and enshrined the modern standard shape. Most of the features that lead to RSI and slow typing, as well as ugly beige/gray plastic everywhere, can be blamed on the Germans.
That and cost cutting. We got rid of all the (inflation-adjusted) $1000 keyboards and downgraded to $300 keyboards in the 1980s. Then in the late 80s we downgraded to $100 keyboards, then $30 keyboards, and ultimately by 2000 or so we got down to $5 keyboards. Can’t really blame any country in particular for the cost cutting, but it’s hardly a surprise that a $5 keyboard isn’t as nice to type on as a $1000 keyboard. On the upside, even while keyboards turned to ****, personal computers spread to every corner of the planet.
As for the metric system... it sucks in many ways, but at least it’s standard. Thankfully the French revolution’s terrible metric time system and metric angle measures never caught on. Too bad for electrodynamics students that MKS units displaced CGS units. Overall the Metric system is definitely helpful compared to the “imperial” system for undergraduate science students. I’m not at all convinced that it helps anyone else, but it’s also... okay. In the kitchen it’s nice that metric users tend to weigh dry ingredients instead of using volume measures, but on the flip side everything measured in decimals creates a lot of unnecessary arithmetic. Temperature in °C is inconvenient compared to °F for human-relevant comparisons but it’s not really too big a deal. cm and meters and km vs. inches and feet and miles is pretty much a wash, for practical purposes. I do like hectares better than acres. ISO paper sizes have an ugly too-skinny proportion (√2) and are hard to design for because they don’t fit a grid, but it’s not really that big a problem in the end. I like A6 size pocket notebooks pretty well.
Personally, I wish we could all switch to using a base twelve number system, and a better standard system of measurements based on that.
