Holding it on your hand is insufficient. Using it may require an external server or certain chosen proprietary software that could be taken from you at any time or itself requiring an external server.

The bits you want to own must be entirely self-contained, and able to be screwed using whatever software you may choose, especially open source (though if the format is fully documented so that anyone can create and distribute a viewer, the software need not be open source.)

See also, The Right to Read. https://www.gnu.org/philosophy/right-to-read.en.html