Several months after happily purchasing an iPad mini 6 (with the Smart Folio, no less) in the winter of 2021, I actually decided to let it go last year.
On the plus side, the greater display size of the mini 6 was a bonus, as was the Apple Pencil 2 compatibility. I also did use it as a small external display for my Macbook Air or Pro from time to time.
On the minus side (for me), I really had troubles with actually being productive with it. Every time I wanted to to type a note or an e-mail, for instance, it felt like the virtual keyboard filled half the screen (which it actually might have), which was pointed out by
@Shin-Ra. In retrospect, the difference in screen ratio (4.6:3 on the mini 6 vs. 4.3 on the mini 5) seemed to make a subtle but noticeable difference, as
@Realityck hinted at. This got really frustrating, because all the content in the upper half of the screen (in landscape mode) scrolled around wildly when you tried to select things or move around in an e-mail, note or document, due to the limited screen space. I guess only I am to blame, because it really isn't meant for working on documents or doing anything that requires more than a modicum of screen space. It wasn't my main device for working by any means, but I thought it could be helpful on the go in a pinch. Sadly, I felt more frustrated by it than expected, when push came to shove.
The Touch ID on the mini 6 also didn't work as well for me as the one of the mini 5, perhaps due to it being a side button that usually necessitates being touched with either index finger rather than your thumb. My skin does tend to get dry in the winter anyway, so Touch ID on any device is an iffy proposition. It must work better for other people, I suppose. Likewise, the volume button orientation that changes when you switch between portrait and landscape in one of the four possible orientation also threw me for a loop rather often, although it wasn't a reason for letting go of the mini 6, just a personal peeve.
For me, I found that I just needed a device to do some journaling in Day One or writing in Ulysses using handwriting with the Apple Pencil, along with some other light use of Evernote, NotePlan and OmniFocus. I also missed not having an Apple-designed external keyboard that could be docked with the unit (as mentioned by
@VampyricGentleman ) as with its larger siblings, such as the iPad Air. The mini 6 was more limited than I expected in all the above respects, I felt.
In the end, I ended up purchasing an Apple-refurbished mini 5, and that has been great for my needs so far. I wonder if Apple is going to stick with the current form factor of the mini 6, if and when they release the mini 7.