Paul McCartney:
"The thing that really made me sit up and take notice was the bass lines on Pet Sounds. If you were in the key of C, you would normally use the root note...a C on the bass. But you just get a completely different effect if you play a G when the band is playing C. There’s a kind of tension created."
That tension is created because when the brain hears an inversion (what McCartney is in the above quote referring to), it yearns to hear the chord "resolve" (return "home"). Brian Wilson uses chord inversions (which he played on piano) throughout "God Only Knows", to great effect. But remember, Wilson often wrote parts for three basses: a 4-string electric, a 6-string electric, and a 4-string upright acoustic. He has them playing all kinds of interesting musical parts throughout Pet Sounds. Very sophisticated writing, far above the level of his peers. I consider "God Only Knows" to be amongst the greatest songs of the 20th Century.
Learning about inversion is what radically changed McCartneys bass playing, first heard in the Revolver album. Very different from his playing on Rubber Soul, before he had heard and absorbed Pet Sounds.
To hear the master of using inversion in bass playing, listen to James Jamerson in Jimmy Ruffins recording of "What Becomes Of The Brokenhearted", as well in "Ain’t No Mountain High Enough" by Marvin Gaye and Tammi Terrell.