RHF wrote:

...
- It doesn't make the antenna any better.

? More Signal Out is Not Any Better ?

- It improves the system performance by reducing
- the reflected mismatch at the generator end of
- the transmission line.

So - All the 'reflected mismatch' is now trapped, wasted,
consumed as a Power Loss in the MatchBox ?
Or - Just may be does some of the 'reflected mismatch'
now get Radiated as Signal Output in the Antenna ?
.

Yep, the matchbox introduces more loss, no matching network which I am
aware of is truly lossless. Heat is the only way I know of to "lose"
the signal.

If your rig had the correct input impedance to negate the use of a
matchbox, you would suffer none of this loss ... the antenna would then
deliver all the signal it was capable of to the rig.

Regards,
JS