Addendum: If you want one, check with Amazon for the availability
of the Free, 200MB/month of T-Mobile data for the life of the
computer.
This is a great feature. 200MB isn't a whole lot but you can
do hours of surfing the web, email etc. for free. Forget about
streaming videos and movies, however. But, OTOH should you
decide you want more data you are able to purchase it from
the T-Mobile webpage. There are times when you want or need
the Internet and there are no wi-fi hotspots available. This
T-Mobile data connection is good where ever there is T-Mobile
cell phone connectivity. The SIM card is for data-only. I don't
know of there is an option to exchange it for a telephone
SIM Card but it wouldn't make such a great phone anyhow. It's
a little too large. For use as an emergency phone you could
install a wi-fi phone app and use it that way over your data
connection.
The Stream 8 has, Mobile Data, Wi-Fi, Bluetooth, GPS (GNSS).
Turn them all off in Settings if you aren't using them as they
consume considerable power from the battery and will shorten
your battery time.