are they longer lasting due to the obvious no rusting? do they require the same level of sealing?

decreased weight and friction – same level of sealing required but longer life.

Only obvious downside is price imo.

Any BB bearing is scrap once shite gets in it for any period of time. It doesn’t matter what the balls are made of.

Ceramic bearings are potentially lower friction, which is relevant if you can pedal at tens of thousands of rpm (ceramic bearings were first used in turbochargers iirc) but in an MTB BB, the design of the seal is more likely to be the friction-deciding factor

The main benefit IMHO is profitability for the manufacturer and retailer!

Hybrid bearings (with steel races) are No lighter really either. Full ceramics are very durable (material is harder than any contaminant, so doesnt wear) and spin freely, but are very pricey and can be fragile. Plenty of stories of bearings in hubs cracking under load.

Well having tried Fsa k-force carbon/ceramic chainset, can honestly say best new biking product I have used in recent years.
It,s like comparing rockshox revs to fox 36 stiffer and smoother =winner!

If you can actually feel the reduced friction in ceramic bearings well done. You’re alone in that! Stiffness is nowt to do with the BB!

Thing is replacing an old worn BB, the new one will always feel smoorther.

I have fitted hope ceramic BB to one bike and hope steel BB to another at the same time and couldn’t tell the difference. But the ceramic has outlasted the steel by 18 months so far.

It was a bb30 mind.
So stiffer and could notice straight away less friction and it being smoother.
I,m not a fast rider either at the mo but still can feel the difference of these fancy tech advances in mtb,s of recent times.