19/13mm fittings popularity?

[qbazdz]

Is it just me, or is the 19/13m size tubing and fittings much less common?
I had been using it what seems like forever but it's now really hard to come by some on MM..
Any reason for this?

 

[qbazdz]

I haven't looked, but EPDM tubing not available for 19/13mm?