I didn't cover the case of smart contracts, but it's essentially the same thing.
Ok, and what concrete, real examples does not benefit from that?
For example, this could be a rendering problem: you provide the models, a distributed system computes it (for a cost). This system cannot be private, efficient and reliable. It can be private and reliable, but hugely inefficient, or efficient but non-private and non-reliable. With a non-distributed system (i.e. Google compute, Amazon cloud, etc) you get pretty much all 3 of them, with a slight caveat that privacy is guaranteed circumstantially/legally instead of mathematically. But it's extremely safe to assume you'll be fine.
You want to run and real time multi-user application.
For example, and MMORPG. This one is a fun challenge for sure, but it's a complete nightmare to develop, and again needs sacrifices. In this case you probably can't achieve speed, security, and large number of players simultaneously. Every decision (like "what did this monster drop?") needs to be done through some large scale consensus to guarantee security, which kills latency completely. If you're extremely lax with security and consistency, then you can probably make it work, but accepting users might cheat, possibly game-breakingly. Or you could achieve it all with a handful of players, and reasonable efficiency[1], but your scope will inevitably be limited. I believe Ubisoft's ForHonor[2] uses P2P gameplay, but I'm not sure how safe their system is. Also I'm sure stats and most persistent data is stored centrally.
[1] See Mental poker:
https://en.wikipedia.org/wiki/Mental_poker
[2] Some reddit discussion from quick googling:
https://www.reddit.com/r/forhonor/comments/5u8jlh/why_forhon...
Note that the players largely loathe this system.