Same as having measures of 2 beats or 4 beats. What makes the difference is like you noted is in the music phrase lenghts.
But again in you can have the same music written in either 2/4, 2/2 (cut-time) or 4/4. IMHO it does depend on how the music is written on paper and how the musicians relate to it.
The Hendrix's song is clearly in 12/8 with a strong 4 beats per measure.
The Animals' is not so obvious and could be open for a real debate on if it is a 2 beats or 4 beats groove![]()
When is it a good idea to write in 4/4 with notation "2 eighth notes equals 1 quarter plus 1 eighth."
and when is it a proper thing to write in 12/8?
How would you noted the following song?