I do have a smart phone, which I use mostly for messaging and (gasp) phoning people! It does get my emails, but I only use it to scan subject lines because I need my reading glasses to read properly on it.

For proper reading and writing (and gaming) I use a desktop.

I was taught that a paragraph should be as long as it takes to cover a specific point.

Calls for shorter paragraphs, shorter sentences and restricted vocabulary quite generally emanate from those (mostly under 40) of meagre education and with the attention span of a brain-damaged mayfly. Bad news, kiddies, I'm not here to coddle you! Learn some words and find out how to concentrate!