If this value is too low, you will get out of memory errors when your loaded content and scenes would not fit into the available memory. But if you set this value too high, your content might fail to load in some browsers or on some machines, because the browser might not have enough available memory to allocate the requested heap size.
With the default value of 256
my game encountered an exception. When raised to 512
it runs fine.
What is a safe memory size for WebGL builds that is unlikely to cause my content to “fail to load in some browsers or on some machines”?