Interesting discussion!
I am a professional player for 35 + years. I've worked for a very well known country artist and filled in for many, many more over my career. So this is just my experience and opinion!!
Now of course, I usually don't read charts on my current artist's gig, BECAUSE I HAVE PLAYED THEM A MILLION TIMES. Why would you need a chart then?
But in the beginning, absolutely! And every new album that my artist comes out with, I will chart, but lose the chart after rehearsals.
My first gig for my artist was on a TV show....I had one rehearsal...at soundcheck for the TV show! The chart was at my feet. I didn't miss a note.
Every once in a blue moon my artist will call an obscure album tune or want to learn a new tune at soundcheck to perform that night.
So, I have a notebook filled with every tune my artist has ever done...including covers. The other guys in the band call me the "Scribe" because I write this stuff down religiously ...so they are always asking me,"what is the key"?..."who is in at the top"?..."arrangement"?.... "how does it end"?
Now to you guys that know the entire catalog of...."insert favorite artist/band" (ie, ACDC) here...because you have heard and played these songs a million times and your band performs it exactly like the arrangement on the record .....why would you need a chart? Because you have played and KNOW these songs!!
BUT WHAT IF NEVER HEARD OF ACDC?? (indulge me) How would you get through the gig??
Also, how many cover bands have different arrangements? OR Medleys?? (one song running into another into another)
My ex is singer that plays with several different corporate and top 40 bands....all different arrangements and keys. She has an iPad with all the different arrangements.
What if you are called for a gig the day before AND you never played or heard one of these songs??
Believe me, it's happened to me, many, many times.
There is no way that I would have made it through those gigs without charts... I'm sorry, I can't memorize 20-30 tunes in a day and feel comfortable playing a concert in front of thousands.
I don't care what it looks like...I care what it SOUNDS like and I've made through many, many of these situations. In fact, I have been asked back multiple times.
What if your called to do a Broadway show? Can you read standard notation?
A recording session? In Nashville everything is number charts and if you have the skill, you can notate kick drum patterns and melodic runs....you have to do this as quickly as possible. Tick Tock!
I will say this, I have gotten many more gigs because I can read than not!
Of course there are are many, many more variables involved in getting a gig...do you have an easy going personality?...can you groove?...are you going to deliver in a high pressure situation?...can you get along with multiple personalities? (this is an echo of point 1)
It doesn't matter if it's chord charts, number charts or standard notation.
AND oh yes, I have paid my dues playing in top 40 bands...we would learn at least 3 new songs a week and occasionally I would have a chart and lyrics on stage for the new song, but only for the first few performances, then it's off the chart.
Bottom line, if I am playing the tune more that 2 or 3 times, then I am off the chart.
If it's just a one-off filling in for another bass player on another artists gig...charts. I will probably never play those songs again, but I will have the charts cataloged!
Keep it Low...