You may not wish to play anything in a Flat Key, but if you try some - maybe a leettle struggle at first, then once you get past that... some tunes just sound RIGHT in a flat key!

Tunes were written in a flat key for different reasons - I think it all depends on what music it is & who you are playing with.  

I never wanted any obstacle preventing me from playing along with any recording.

From Keys Thread (2024):  

I hear a lot of great music to play on the fiddle - in flat keys. 
Ethnic folk music, blues, jazz, etc... have plenty of flats/flat keys, even if you only consider G Minor - MANY trad Irish tunes listed at thesession.org in G minor that I like (and other flat keys, too)!  
Related discussion at The Session:
Your Favorite Tunes in the "Flat" Keys. FMaj, BbMaj, Gdor, Gmin (Irish & Scottish).
I believe a lot of Scottish music (especially in relation to GH Bagpipes) use flats/flat keys.  
Once there is 2 or more flats in a key signature, I know my pinky finger is going to get a workout!  

Geez, well over a year & I've gone down another rabbit hole.  

I understand some keys sound better naturally on the fiddle, and I probably like more than most because I have more strings that can resonate.  

Something happened last year that got me more interested in looking at tunes with flats to learn - when I accidentally composed a tune using Cmin. 

From pg 14 of my blog (2024):

Whew! 

Felt MUCH better playing 'Wistful Thinking' today! 

Can't really understand why the Cm stuff gave me grief yesterday.  🤔... come to think of it, not so sure I've ever played anything in Cm (before this). 

Ah HA!  Looked to see what tunes The Session had in Cm... they don't even have Cm as a key option you can search for! 😳 🤣

...still missed a couple of those fancy staccatos, though.

I don't have ANY problems with this now (played it on & off enough), maybe everything else just seems easier because of it? 

Started to notice I was playing tunes I heard in flat keys & it didn't even dawn on me what they were!  I hadn't played 'Fly By Night Hornpipe' (version I learned from a Joe Burke accordion recording) for quite a while, so looked at the session to see if I was playing it right (it's pretty much the 4th setting) - surprise... EbMaj, but shows the wrong key because there is no choice (later I found a work-around).

After that it seemed like 'Flat Keys' were coming out of the woodwork at me!  I had started learning 'Zito The Bubbleman', and again - no settings on The Session matched the recording I'm learning from (I've since added the setting in BbMix!).  Love I've been playing Roslyn Castle in Cm - 3 flats!  Ran across more, but I'm brain-dead at the moment. 😵‍💫

The strange thing to me (for some time now) - the issue of VERY LIMITED FLAT keys available in the search drop-down box on The Session. 

Well... curiosity got the cat & I had to start a rabbit hole of a discussion there a few days ago, which is pretty interesting - been learning a lot.  

Views on Bb Major & Eb Major in Playing ITM and Trad Scottish Tunes? on The Session

Suppose some folks are going to be sorry I ever learned anything about ABC notation and the 'Modal Circle of Fifths'. 

 ...flats, flats, flats, flats, flats.  

...and this too, shall pass - but I'll probably be a bit obsessed for a bit.