I think we should get back to the original question ,
(which to me at least, is much more interesting than if something is marketing hyperbole or not)
first observation I’d have, is the decision of laptop vs single purpose (SPC), I think comes often down to what musicians want and to some extent technical background.
I think generally to get the most out of SPC requires more investment in time, and often more technical knowledge to get the most out of them - and this is rewarded by a real sense of building your own instrument.
note : I said generally, there are exceptions to this, some just use ‘as is’ with patches developed by others.
given that, I can only ever give a personal opinion, so this is mine, based only on what I own and actually use ( and I get asked quite a bit about this )
laptop - I use for DAW, and for other software, also where I want a screen.
they come in all shapes and sizes from $500-$5000, you can make it an instrument, absolutely no problem - with some midi hardware/controller , you can make it so you don’t need to interact directly with it whilst making music - technically it can do anything the following can do (at least software wise)
rPI (w/ PiSound for me) : its pretty powerful, cheap, enough that you can easily dedicate it to a single purpose e.g. an FX
really cost is the driving factor - its cheaper than most guitar pedals, so you can have a few lying around that just wake up and do their thing 
Bela (w BeagleBone Black) : for me this is all about I/O an minimal latency, because of its analog I/O (5v) , its very easy build your own instruments and interface it to other things, and the low latency kernel and PRU use, make it ‘feel alive’ (much more than rPI solutions)
Bela Salt: so the eurorack module form of Bela, ok this was a bit expensive.
But I’ve used it SO much , code portable from Bela, same low latency.
BUT I love being able to integrate computing power directly into eurorack with direct CV I/O its awesome - and being in the rack, its not something cluttering my desk.
I think the beauty of SPC in a eurorack form, is not only are they versatile, but you have them surrounded by other modules to supplement them, and it feels all so natural… e.g. you can do things like create weird digital oscillators but then feed them into a lovely analog filter… or drive it by a eurorack sequencer.
… so you don’t have to build everything on the SPC.
(my latest projects is using one to integrate Eigenharp and Soundplane directly into Eurorack)
Bela Pepper is going to the lower the entry price considerably to this, and Im super excited by this!
Axoloti : I love axoloti
- its straight forward and to the point, ridiculously cheap, and much more powerful than specs would point out (because its pretty close to bare metal) - its also really easy to interface it to things directly, and again much lower latency than a rPI .
but, again its cheap enough you can use it more like a pedal. (lots of people own a few of them)
Organelle : this is really the ‘odd one out’ for me, partly because its not cheap ($500) , but the reason I love it, is it 100% complete - it has a keyboard, screen, controls - you need nothing else to just play it on the couch, and being a complete form factor, i can develop patches for it, and know every organelle owner can use them if they want…
also because of this, and the number of patches (and I guess time its been around), it has more musician using it than others… a less ‘technical’ audience.
Nebulae : ok, I’d actually disagree in some ways with this being in the list.
what Ive learnt, is it seems 95-99% of Nebulae owners are only interested in the granular looper, they are not really that interested if is a rPI, or thats extendable or not, and in that sense it’s not that different from any other digital module.
(and things like O&C would be better to discuss really but then the topic will quickly turn into ‘multi purpose’ modules vs single purpose!)
but as a programmer for sure, it’s really nice to extend, and I hope to help improve the support for 3rd party modules on it - and then much of what I said about Bela Salt is applicable.
thats it , I think … Im a bit of an addict to them, but thats also because once you get deeply into one of them - you tend to find your code and knowledge is portable to others , so the time investment is reduced - and so from there, I just pick n choose between them based on the various different properties they have…
I hope, in the above Ive shown , where I think each has its strength…
one last thing, Id say is…
ALL these SPC have great communities, where you can get help, and advice (as well as patches) , and also some great discussion surrounding building instruments - for example, they helped me gain the confidence to start building hardware - and helped me through that process.
… and I think that community spirit, is also part of the attraction to me.