It depends on your lifestyle. I'm married so tablets allow me to have a window to the internet whilst I'm in the living room with my wife. Most of my postings are done via one of my tablets, currently mainly my Huawei Mediapad. I also watch YouTube quite a lot, in bed and in the bath, so I have a 10" Teclast tablet I use for that. I do most of my reading on tablets (prose & comics), most of my shopping and no matter what we're watching on TV I have to have IMDB immediately at hand.
I know your lifestyle is quite different to mine so there might not be as many uses for them for you, but for me they're invaluable devices.
My phone is basically a mini-tablet for out of the house, a camera (stills & video), notepad, calculator, media player (plugs into any HDMI port with an adaptor), torch, mirror, voice recorder, video conference platform & more. My previous phone is a dedicated music player now - lives in the kitchen & the car.
It's funny, all of this stuff probably sounds common and makes total sense to many of the people on this forum, and most people in general. But it's always baffled me.
Like, my parents... in their 60s, kinda inching towards 70... are on their phones CONSTANTLY. You'd expect them to be tech inept due to age, and.... in some ways they are (normal computers, they sometimes have issues with), but those phones? ALL THE TIME. Facebook and texting and news reading and basically everything. I've frequently asked them why they even have the big freaking TV, if they're just going to stare at those shrunken screens all the time. And that's how it is with everyone in the family. Except me.
I myself am usually the keeper of the Tech Vortex in the family. All the craziest tech, the most powerful stuff, the most insane gizmos, usually are under my control. I can sit there in freaking VR with floating hologram keyboards and interact with the computer like that (hey, it spices things up a bit), and it seems normal to me. And if someone is having a tech problem with their stuff, they usually come to me (despite that me fixing stuff is like duct-taping a car back together... but hey, they dont need to know that part). Heck, even the modem and router are in my room, since if that thing goes bad, I get the hilarious fun of dealing with it.
But not those phones. Even for all of my years of tech use and having grown up with computers, I never have, and will never, understand everyone's obsession with smartphones. I just dont get it. Yet even the older people in the family do get it. It's like a paradox. Much of the family finds this absolutely hilarious.
Even having an iPhone myself, and.... yeah. I dont get it it. And it's hard to explain why.
Heck, I remember when I got the iPhone I currently have... which was due to the other one vanishing... the guy who came to the house to deliver/sell it, said something like "boy I bet you're excited to get the new model iPhone, eh?" and I said something like "It's mostly a security device, I barely touch it otherwise" and he looked at me like an entire bear had just crawled out of my ear. Definitely one of those "I didnt drink the Kool-Aid" moments.
I will say though, the phone does get used to browse memes on Imgur if I'm bored out of my mind over at my mom's house or something. So.... there's that, at least.