Does 'interval' matter in FuncAnimation when saving to a file with a specified fps?

Question

I am using FuncAnimation to generate an animation which I am then saving to a .gif via PillowWriter. FuncAnimation can take an interval value which would normally define the time between frames if shown in the figure window, but PillowWriter takes a fps value which as far as I can tell overrides the interval. The code is roughly this:

anim = FuncAnimation(fig, myAnimateFunc, interval=100) #100ms = 10fps
writer = animation.PillowWriter(fps=30) #30fps = 33.3ms
anim.save('myAnimation.gif', writer)

The .gif file is definitely using the fps value from PillowWriter, but several tutorials about saving animations include the interval so I was confused. Does the interval matter at all if I'm specifying fps? Would decreasing it to 1 speed up render time by removing unnecessary downtime?