the first one, could sound dumb but is ideal for people on diet, when you eat too fast and don't masticate your food properly, you usually end eating too much, you don't digest well and that leads to overweight so monitor that and try to do something about it could help, sound like a not properly oriented idea but has space to grow
about size of phones, well, that depends on how you use it, i have seen people using the galaxy note as phone at 5.5" and doesn't look bigger than the iphone with the 4" screen and the weight, i think that the maximum weight should be 150 grams, my phone is 136 grams, thick at 18 millimeters, almost 3/4" and believe it or not, i have to check if it is still in my pocket from time to time, no pocket is broken yet so you get used to anything, specially if you enjoy using it like i do when using it as netbook replacement, even with a 3" display
what i really find dumb is that 20" tablet with 4K resolution, not a tablet(it must be really heavy) and you don't need nothing more than 1080p at that size, maybe 2560 maximum, this is not a retina display thing or something
the phone case, once i saw a woman making a call with a iphone case that works like a book cover like this one

she looked so dumb using it because it was harder and couldn't be folded back while making the call, almost like talking to a book
the price could sound expensive, makes me remember the dolce and gabana motorola razr v3, it didn't had anything different than the normal v3 but used to cost triple just because it had a logo and it was gold colored
it is just fashion, expensive fashion