Does length matter ?

Of course you should if you can.
By connecting speakers to an amp you are creating (or extending) a circuit and, since in stereo we have two channels, i.e. two electronically identical circuits, it's good to keep them that way. By using wires of different lengths, the circuits are dissimilar.
The sonic effects are, of course, minimal in most cases

There's no technical reason to keep them the same length (within reason). That cable is 1.03Ω/1000ft, so if you had one 10ft and the other 20 then the difference in resistance would be 0.0103Ω which is negligible and will make no difference to the sound quality. If one is longer than it needs to be then you may inadvertently create an inductor where it coils back on itself, this is also unlikely to impact audio unless there are a fair few turns.
If you are worried about the time difference between the cables, for the 20 and 10 ft example it would be around 10 nanoseconds or 1 cycle at 100MHz... which is again negligible in audio.
I suggest the best thing to do is to cut each cable the length it needs to be to reach from the amp to the speaker.

I don’t believe you will hear a difference in the music with different speaker cable lengths however should you ever want to sell the speaker cables it would most likely be more difficult to accomplish. I personally have not heard a difference with two different lengths of speaker cable.

As @lak said, it matters if you want to sell them at some point.

Technically it matters but you might never hear s difference.