It is difficult even getting a gym membership (yes, there are alternative such as pay-as-you-go at ward gyms) without a bank account. And if you are from a country such as the USA, obtaining a bank account even with a residency (zairyu) card is cumbersome on account of FATCA (some banks will even outright reject Americans unless they are on a corporate expat package or are working for a Japanese company which "takes care of things" for them).
These hurdles, along with many others, make Japan a difficult proposition for typical nomads.
Show up in a new country...
>Let me rent a place
No zairyu? See ya! (yes, there are sharehouses and places which allow foreigners for medium to long term stays, as well as expensive corporate housing type places, but you are limited to options such as these)
>That sucks. Well, let me get a local phone number because that's required for some services
No zairyu? See ya! (yes, there are now more MVNOs and services which will allow foreigners to get temporary Japanese numbers but at a higher cost)
>Alright, what a frustrating day, I'll go to the gym, and I'll bring a wad of cash to pay for my first 3 months membership until I get everything set up
No bank account? See ya!
Are these things surmountable? Of course. But even for foreigners who speak Japanese decently well (such as N2 and above, though N4 is still probably more than enough to navigate basic bureaucratic procedures), navigating these almost circular tasks is not any easier. Are these things that a nomad wants to deal with? lol, *highly* doubtful. Even for foreigners who can speak Japanese and who are studying in Japan or have a job at a Japanese company, there are many hurdles that take time to set up to get fully "situated" there.
Japan is not structured for short term knowledge workers. Heck, it is not structured for even most foreigners (enjoy being stopped on your bicycle by police for the sole reason that you do not look Japanese). Every year, the Japanese government comes out with new initiatives to attract knowledge workers, from the Fukuoka startup zone to the "blue collar labourer visa" to the "PhD visa". Yet they can never even come close to meeting quotas, because the hidden requirements of these visas, combined with friction/hurdles that still exist upon arrival, render all these attempts stillborn. These initiatives are done such that the Japanese government and government-controlled press can say "Look, we're trying!", without doing anything substantive.
Now, Japan *is* structured for short term labourers from Southeast Asia and countries like Nepal, but poor conditions in factory dormitories and having your passport seized upon arrival are not exactly the types of jobs that HN readers have in mind.
Don't get me wrong, Japan is a beautiful country to visit, with a rich history and culture. And if you are a foreign expat on a nice package, there is good money to be made. Students on semesters or years abroad? Probably fun, as well! But as a short term digital nomad? That's a huge ask. So many barriers that do not exist nearly anywhere else in the world for your typical digital nomad reader here. If you want to see Japan, it is probably best to just travel as a tourist. [Side note: even for long term foreign workers in Japan, the new laws passed in 2015/2016 are brutal for foreign income, high taxes on global assets, which caused a bit of an exodus of highly-paid foreign expats. Those taxes hit after 5 years spent in Japan as a resident, so your time is limited to 4.99 years if you want to avoid them. Not relevant to short term digital nomads, but just pointing out that, if anything, Japan is increasingly unfriendly to skilled foreign workers, not that other way around. There are *always* massive strings attached when it comes to "friendly" initiatives from the Japanese government.]