Yes there is a reason, actually multiple.

If you get a resonable speed CF card it should be pretty fast, but more to the point I see 3 advantages:

1.) I am trying to make a tablet design, hence space is at a premium CF Cards = Small

2.) CF Cards are very vibration resistant. (I was considering putting this project on a vespa)

3.) Retrieving data from a CF card requires far less energy than spooling up a HD

But there a re downsides, they are pricy as far a storage i.e. 8gb = $130+ and speed can be an issue and again faster cards are pricy.

Just a couple thoughts.
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