That depends, of course. For media consumption you might want a bigger screen. For reading you might want a smaller screen. Many will want a more mainstream OS that plays better with all their apps and various DRM. Some will want a more capable OS, like Linux or Windows. Some will want iOS, for some unfathomable reason...

For me, a big portion of what I want a tablet for will be covered by the Pixel Tablet on Graphene. That is multiple profiles, for work, play, and banking.

• Most of my banking apps are available, and most importantly so is YNAB. My phone is kept with a very minimal app footprint, and no Play Store in any capacity, and I don't particularly like budgeting in my browser either on my phone or laptop.
• I don't let work anywhere near my phone, but occasionally I do want to check Outlook or Teams without jumping into my work laptop. I also need to monitor some things actively for hours on end, so it would be nice to be able to do that from the kitchen, living room, or patio without having to go through the nightmare that is un-docking and re-docking my work laptop that runs Windows. Luckily work lets me Intune join a tablet so long as it's not rooted, others may have stricter OS limitations though.
• Sometimes I just want to chill out on the couch and watch a movie or TV show. I don't have a TV, and if I'm on my laptop I tend to put the video in PIP and divide my attention. A tablet makes me far less likely to do this.

I prefer Calyx on my phone, for the sake of the extra privacy of Micro-G vs sandboxed Google Play Services. But most of my tablet use case tends more towards mainstream, so I think the compromise is worth it for the more robust multi-profile support in Graphene. But hey, Calyx supports the Pixel Tablet, too.

But... part of me still wants a tablet with a full Linux distro on it, so I'm tempted by stuff like the Starlabs Starlite, and the upcoming Minisforum Ryzen 8000 tablet. But I won't have a streamlined OS that minimizes distractions, and unless I run Ubuntu LTS I wouldn't be able to use it for anything work related. There are also a lot more DRM limitations in regards to streaming video.

Point is, everyone is going to have their own special use case. I'm just glad we're finally getting some FOSS capable tablets into the market, be they running AOSP or Linux.

The thing holding me from GrapheneOS is mostly Hub Mode on my tablet.