Modes developed historically because some instruments had fixed pitches and could not be changed quickly.
Think of a small handheld harp. The strings might be tuned to what we'd consider a C Major scale: C D E F G A B C
How could such a tuning accomodate a song needing a minor feeling. Modes hold the key. Base your melody around D, E or A and you will create a minor
sounding tune. Support that tune with 3 note (every other string) combinations around the selected root and you'll hear:
D-F-A = D minor
E-G-B = E minor
A-C-E = A minor
Historical examples of folk songs in these minor keys abound, for example:
Greensleeves - D Dorian - D dorian
What Child is This? - A Aeolian * The melody and scales differ by the position of the 1/2 steps in the scale:
Dorian has 1/2 steps between the 3-4 and 6-7 notes
Aeolian has 1/2 steps between the 3-4 and 5-6 notes
E minor - Phrygian scale is common in "spanish folk music" like Malaguena
Play an E monor chord followed by an F major chord and back to Em and you'll be inspired to a flamenco improvisation.
So, the modes create cultural references for us and can be used to generate fresh melodic ideas and solos. On stage they can be a use tool for a working musician but only if you want to extra spice of the less well worn paths of musical expression. Major and Minor scales will make you sound perfectly western and as I was once accused of being: "the whitest soloist in the band" because I just didn't know any blues scales on the flutist.
It would be very difficult to play modern pop music without a resoanble facility for the blues scale or at least pentatonic scales as a subset.
Pentatonic uses also come from historic instruments with fixed pitches that
emerged in all the major cultures around the continents. Pentatonics also allow for the focus on a root that generates a major chord reference and a minor chord reference depending upon the start and end points of a melody and the selected chords chosen from the available set.
As an artist you can choose the tools and colors you paint with that express your aesthetic. There are no rules... just choices.