Did the girls appreciate it?
Not even an inkling. You see it was a sulf-natrium, calcium, magnesium hydrogen carbonate bath. For fellow non-scientists that means it stunk like rotten eggs. Not stunk really, more whiffed? Was odorous? Well, however you state it it had a certain fragrance.
And that fragrance completely blinded the girls to the beauty of the scenery and the luxury of all that bath hopping and the miracle that we arrived when it wasn't crowded and all that.
Nope. The only comments were:
"It really stinks!"
"Did someone pass gas in this onsen?"
"... and this one?"
"All the baths stink. Mummy let's go! This place is yucky!"
So, Hirayu onsen. Beautiful, luxurious, good enough for feudal lords, but just doesn't pass muster with the pre-school crowd.