Wikipedia also says it uses steam, not just hot air, and again doesn't say anything as to why
Do you know why pressure and steam help?
Edit: I may have found it while looking at what I thought was an unrelated part of the rabbit hole. Gravity displacement sounds like antigravity technology but it's apparently the cheapest autoclave type and means "displace using gravity" (by letting gravity do its thing; not adding in a vacuum pump). What it's displacing is air. This matters because
> Steam at 134 °C can achieve a desired level of sterility in three minutes, while achieving the same level of sterility in hot air requires two hours at 160 °C. (—Wikipedia)
I'm now assuming that pressure must help push the air out, and steam is used for having better heat conductivity. Neither is quite spelled out but that's my best guess currently