why was 'on' changed to 'lazyLink'?

[pixelzoom]

In a50707b for phetsims/scenery#490, @jonathanolson made this change in ConcentrationMeterNode.js:

-     solutionNode.on( 'bounds', updateValue );
-     stockSolutionNode.on( 'bounds', updateValue );
-     solventFluidNode.on( 'bounds', updateValue );
-     drainFluidNode.on( 'bounds', updateValue );
+     solutionNode.boundsProperty.lazyLink( updateValue );
+     stockSolutionNode.boundsProperty.lazyLink( updateValue );
+     solventFluidNode.boundsProperty.lazyLink( updateValue );
+     drainFluidNode.boundsProperty.lazyLink( updateValue );

And in phetsims/scenery#490 (comment), @zepumph asked why on was changed to lazyLink instead of link. I'm interested in the answer.

[jonathanolson]

It's because I was going for compatibility, and since .on() only added the listener without calling it, lazyLink is the appropriate thing to change it to.

[pixelzoom]

Great, thanks for clarifying. Closing.