Both of them measure 5-10% CPU for me. The iPhone 4 is pretty old and is stuck with iOS 7 - now four versions behind - so if you only see a difference there, it may just be that old versions of Safari don't optimise the JavaScript so well.
I don't think so if it was Anything related to JavaScript it will perform the same (with or without) Containers here you can see very clear just by adding an object to a container without any picking involving between this two objects it affects the performance Badly so I think is a bug from C2 and looks pretty serious
I mentioned Iphone4 because there you can see very clearly the performance drops but the truth all the phones are affected by this, the only difference is that are more powerful phones and they can handle it better but it shouldn't happen that because if you notice there is only code for the controller we don't even move the player yet and still the CPU goes really High so when you ad more events for the Game Logic then is when you will notice the Fps Drops even on Newer phones.
If you cant Reproduce it let me reproduce it for you:
Look for when I touch the screen and start moving the Pad controller how the Cpu goes Up and the sooner I stop touching the Cpu goes to normal plus I recorded on Debug Mode so you can see how the Draw calls is the one causing the problem it may help you more to debug the problem
Results are With Containers Cpu perform Double & sometimes more than that
Tests:
==========================================================
Iphone 4
No Containers
Normal Mode:
https://www.dropbox.com/s/o5em0xb7d9k9b9v/Iphone4%2BNo%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/a97sfiaki735gjh/Iphone4%2BNo%20Containers%2BDebugMode.mp4?dl=0
With Containers
Normal Mode:
https://www.dropbox.com/s/1195dsia704oz9m/Iphone4%2BWith%20Containers_NormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/kffbn5vyclzzkzo/Iphone4%2BWith%20Containers%2BDebugMode.mp4?dl=0
========================================================================
Iphone 6
No Containers
Normal Mode:
https://www.dropbox.com/s/2m0vpnafu7ut5e3/Iphone6%2BNo%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/2ez47lm2o1j4d7l/Iphone6%2BNo%20Containers%2BDebugMode.mp4?dl=0
With Containers
Normal Mode:
https://www.dropbox.com/s/pzxrdfv9d8tspri/Iphone6%2BWith%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/zvzfb3eec65h2bl/Iphone6%2BWith%20Containers%2BDebugMode.mp4?dl=0
======================================================================
Iphone 7 Plus
No Containers
Normal Mode:
https://www.dropbox.com/s/imfq887ei5om32m/Iphone7%2BNo%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/5lecaoremra7apl/Iphone7%2BNo%20Containers%2BDebugMode.mp4?dl=0
With Containers
Normal Mode:
https://www.dropbox.com/s/zu3zxklmh5sbq20/Iphone7%2BWith%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/ob1o2btafom65pn/Iphone7%2BWith%20Containers%2BDebugMode.mp4?dl=0
=====================================================================================
Iphone 8 Plus
No Containers
Normal Mode:
https://www.dropbox.com/s/ztfl8xzqye3shj7/Iphone8%2BNo%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/k66wgkfpyf5wt5u/Iphone8%2BNo%20Containers%2BDebugMode.mp4?dl=0
With Containers
Normal Mode:
https://www.dropbox.com/s/mhurt2tc156du2c/Iphone8%2BWith%20Containers%2BNormalMode.mp4?dl=0
Debug Mode:
https://www.dropbox.com/s/7h256djmgrtttlv/Iphone8%2BWith%20Containers%2BDebugMode.mp4?dl=0