Because smartphones ( and their notifications) are the worst thing you can do to your focus .. they don't offer any advantage over tablet but since they fit in your hands , you tend to carry them everywhere.. even in your bed .. and toilet. With a tablet ( particularly a big one like s7 FE ) you are forced to make a conscious decision if or not you wanna indulge in technology.. tech is NOT bad ..excess of tech is bad just like alcohol or sugar ..

Another benefit with tabs is I do use Samsung pen a lot ..for sketches and notes etc .. if I have phone in my pocket , I noticed I never picked up tablet .. on phones I end up taking voice notes .. which are harder to capture and harder to review .. a sketch on the other hand grows as you revisit them ..

Plus , I save 20 dollars a month.. it's not much but if you add up over years and invest , it's a lot .. I saved almost 2000 dollars in last four years ..invested them in btc , they are worth 10 k now ..

It's kinda no brainer ..smart phones are essentially tracking devices ..even Apple tracks location ..not that I have any issues with tracking personally, but such technologies..when applied to masses , always end up in bad outcomes ..