No, but 1.8 is a big difference when it comes to taking a baby's temperature or figuring out if your meat is done just right. For a child, 99 is considered a mild fevor and is 37.22. 98.6 is considered "normal" and is 37 flat in C. However, if you had a mother trying to keep track of her child's fever over a period of time, the small variations between those two temps would be a lot more important. The total variation between 99, 99.5, and 100 F is so small on the C scale (37.22, 37.5, 37.77) that it's a lot easier to make mistakes in recording or reporting the results. Sure it's easy to do when it's your job in a professional setting, but lay people make mistakes all the time. Using a scale that makes the number differences larger (and psychologically significant, because you can bet no mother is going to forget that her child has a fever of 100) helps reduce those errors.
First of all, using two decimal places is not necessary for recording a baby's temperature, Fahrenheit or Celsius. 37.2 C is equivalent to 98.96 F, and 37.22 C is equal to 98.996 F. The hundredth's place is clearly superfluous. Therefore, your numbers reported to one decimal place in Celsius become (37.2, 37.5, 37.8), corresponding to 99, 99.5, 100.0 Fahrenheit. ...Plenty accurate for household thermometer readings.
I see no reason why 99, 99.5, and 100 are easier to track than 37.2, 37.5, and 37.7. As you said, we accept body temp to be 98.6 and 37.0 in Celsius. If decimals are difficult to remember, then clearly we should pick the scale that represents normal body temp as an integer, right?
There are a lot of measuring cups and spoons that do come graduated these days (no, they're not in the "beyond" section of BBB), but it's not always possible to go by weight.
Weight also doesn't solve much because it would add an additional piece of equipment that isn't needed for a lot of recipes.
Perhaps your set of measuring cups is the additional piece of equipment. Indeed you wouldn't need them. For a recipe in SI, the only items you would need are an electronic balance, graduating measuring "cup," and a graduated cylinder. No series of cups or spoons required (although, they do of course come in metric for those so inclined).
It's also impractical to keep weighing out ingredients, especially if their net weight is going to be in the few grams. You also probably wouldn't save any dishes because flour is usually added into other wet ingredients like butter and sugar separately, so a second bowl would be used regardless.
It might seem that way to you, but the majority of the world uses weight to measure dry ingredients. For them it's just as easy.
Plus it's more intuitive and more accurate to measure dry goods by weight.
Other than that, any vessel marked "30ml" used for measuring would essentially be a tablespoon. A rose by any other name, really. Except that the 30ml rose is clunkier to say. In fact, you'd still need names for all of the common measures even using SI.
Why would you need alternative names? A recipe would call for "30ml" of any given liquid. There's no need to call it anything else.
Is everyone really going to go around calling a cup the "237ml vessel?"
Well, no one would ask for a 237ml vessel because that's an arbitrary number based on a different system of units. But if you wanted, yes, you could measure that amount in a graduated measuring cup (or weigh it on your balance).
Are people going to start calling it the "liter quartet of milk?" What would you do for the measures that have a secondary meaning? Will people still be able to call it a "pint" if it's sold as 500ml?
I suspect people would call it a "quarter liter," much like I would say "quarter gallon."
And no, you wouldn't call 500ml a "pint" because, well, why would you?
...But countries using SI do call 500ml a demi-liter ("demi" meaning "half").
There are some (albeit few these days). For daily tasks, the composite numbers in Imperial units are easy to halve and quarter.
This is the case with Si units as well. 500, 250, 125, 75, etc. Though SI units can also be divided by any number you wish. Want to make 1/5 of the recipe? ...Just divide all the numbers by five.
This has less relevance today with prepackaged food and digital equipment, but at one time it made practical sense for a lot more uses. The residual benefits are still present in home baking and similar activities where base 10 doesn't help, but those are the few things that still make heavy use of standard units anyhow. I don't think it's that onerous to know these days, especially with apps, Google, and conversion charts everywhere around us.
No, but it is onerous for kids to learn SI units, which is a mandatory skill in this global world. Like I said, why teach kids two units of measure if one will suffice?
