At IMVU this feature was quite important. Why? Because we wanted more lightweight integration of 3D avatars with web pages. We didn't want our engine to allocate 300 MB or whatever of memory every time, because every single IMVU browser tab you'd have open would consume that much memory. It's so much nicer to allocate, say, 16 MB and grow it as needed by the use case. Chat rooms, for example, are much heavier than dress up.

I'm rather disappointed to see this turn of events.

For the use case of "load a heavy game" I largely agree with what you're saying.