All antennas are tuneable. Firestick just tries to trick you into thinking theirs are special. Actually Firestick tries to trick you about a lot of this.
How many channels you receive has nothing to do with the size of the antenna.
That little stub, if it can be tuned to the 11m band at all, would have crappy performance compared to a longer antenna. My guess is that's actually a UHF (70cm) antenna. It's about hte right length for that. Or perhaps a scanner antenna, if the person wasn't too concerned about performance.