Where you use a physical keyboard on a mobile device? I doubt while standing on the road, waiting for a train and so on, a physical keyboard is used typically on a table, and in that regard a small laptop is far better since it partially contain "the table": you can type on is on the knees, the screen is "stable" no special support needed, the keyboard equally. Having a typically crappy keyboard, crappier that a craptop keyboard one, + a support to use a mobile device with it's limited an limiting OS, small screen etc is at best masochism.

Mobile is pushed for a reason: it's the best platform for surveillance capitalism, the best solution to profile users and assure they only consume, not create anything significant. For users mobile stuff are just complement of real desktops, those who tried the capitalism narrated model "go mobile, it's the future" never do well except maybe for a short honeymoon timeframe.

Desktop side unfortunately 90% of the substantial development was stopped decades ago, but we still have something and we need it, similarly the "homeserver" model never really took off, but we have something and we desperately need it. The cloud+mobile path is the common Clod Cam you can see on insecam and on the logs of a DDOS attack together with many commercial domestic NAS devices and other "smart" stuff, is the path where "your photos, music, ebooks, ..." exists as long as the third party service managing them exists "for life", of the service, not yours, at the condition the service decide to offer until it change the offer and the price or simply change APIs and your nice app crash and you have to rush to implement something and keep it going IF is still possible, take a look at some Chrome extensions upon Chrome API changes...

Notes might be just the digital equivalent of a scrap paper note to remember the milk, but might also be your college and professional notes for a lifetime, so they potentially hold a BIG value, no wise person can endanger such value rooting it on mobile/cloud land. Oh, and that value is not just the mere text, but also the tools that enable a certain workflow, so the ability to download some MD files does not suffice, at all.