Recently bought 100 feet of 14 gauge speaker wire.

It says on the role, not designed for in-wall installations .

Why not, it's only speaker current?

OTOH, it's 14 gauge. Could I use it for a lamp cord? The insulation is
clear and a little stiffer, but it seems a lot like electrical wire.
What reason is there that it can't be used for electric radios, lamps,
etc?