Some things I found out about media cafes in Japan that I found interesting:

-They often offer all you can drink soft drinks for customers, have food on sale inside (usually frozen foods), and accept delivery orders
-Some operate 24 hours a day
-Some offer a shower room with cleaning products and sleeping items (pillow, blanket, etc.) for free to customers
-They generally sell time in blocks that get cheaper as you buy more time at once and there are even 12 hour night packs that let you stay overnight for around than 2000 JPY a night
-The speeds on the place I went to was around 150Mbps down and 20 Mbps up
-Some places have  computers designated as high spec computers or computers with office programs. The high spec one I had was an i7 with a Nvidia GeForce 5XXX or thereabouts, only a year and a half old or so according to my friend
-There are various room types ranging between open seating (what you might get at a library computer lab), single rooms with a reclining chair, pair rooms where you sit on a padded floor, and single rooms with massage chairs

So I’d you don’t mind sleeping in a chair or on a padded floor, these places are good for a cheap unexpected (or expected) stay.
And you get access to the internet, electricity, ordered food, and a library of manga.
At the place we went to this time there’s a pack that goes from 7am to 6pm that’s for 1000 JPY.
Maybe I’ll try that next time to see how much I can game before I get tired of it.
This isn’t going to end well…