Oh, they're cassettes? I thought they were modules that contained the Memory necessary to run them? That way they'd be useful in general as memory expansion. That'd drive package price up, but the Stat package especially would be portable sans cassette player. Just one expansion slot in the 1000?
I need to pull out my Z88 again sometime. I'd already purchased my PowerBook 100 before getting the Mac setup. There was a Mac connectivity version later on in its lifespan, not sure about time of release, ISTR it was after the PowerBooks were released.
The Sinclair 1000 was way ahead of its time, but the Commodore/Radio Shack juggernaut in the American consumer market was too much for even TI and Canon to resist for long.