If you're strictly taking about the Zero, I'd agree with you, but with the One they're entering a new market. I mean, kind of people who like to mess around with Linux and do hacker-y network-y things are also generally the kind of people who would prefer to use a keyboard, the kind who would love the extra hardware grunt to speed up tools like hashcat.
And of course, the One will be cheaper than a full-fledged x86 handheld, but if you're willing to spend a bit more, you can do so so much more - it becomes a more practical device.
From the FlipCTL description, I'm surmising the intended use case is this as a cyberdeck aka using it for external tasks, vs. hacking on it at home with your actual keyboard. For example you make a config for X task at home and perform X task on the go. I do not see any indication that this is meant to be a primary device
I'm not saying it's meant to be a primary device. I'm simply saying that just adding a keyboard adds a huge quality of life improvement, and the bigger size allows you to pack in more power whilst still being pocketable and portable.
Remember the "easy money" scene from Terminator 2[1]? Ever since I watched that as a kid, that form-factor has been my dream cyberdeck. As I grew older, I went on to own the HTC TyTN and the Nokia N900 - and loved them to bits - but I always felt constrained because of the ARM architecture and low specs. Like, you couldn't realistically brute-force any decent complexity passwords back then, and I bet the neither can the Flipper One with today's passwords.
After being bitten by the various limitations of compact ARM devices, I wanted to get my hands on one of those OQO pocket PCs that ran a full-fledged Windows XP, but never managed to try out. Also missed out on the Sony VAIO P-series. So when the first GPD Pocket came out, I jumped on to it straight away even though it was from some random unheard of company at the time. And I loved it, and haven't looked back since then. I finally had a decent, proper computer in my pocket.
So for me, a keyboard would be a bare minimum on a cyberdeck, and if it's got oodles of RAM and compute, that's even better. And the newer GPDs have also been able to play AAA games on the go, like Cyberpunk 2077, and I think that is super cool.
I did not watch Terminator 2 as it came out before I was born
I find it hard to disagree with you though - I like what the flipper team is doing but I think yeah I would be hard pressed to find a use for a device that doesnt have a keyboard when I have my phone already handy
And of course, the One will be cheaper than a full-fledged x86 handheld, but if you're willing to spend a bit more, you can do so so much more - it becomes a more practical device.