AVR-Chat

I realize this is off-AVR topic, but why the sudden(?) proliferation of
putting parts in moisture-sealed packaging (e.g., by Digi-Key and Mouser),
when they were previously not so packaged?  Must the accompanying Threat of
Dire Doom be taken seriously if limits are exceeded?   Why does it seem
limited to just SMT devices and not DIP?

Thanks, Steve