Why is a three-tier architecture of a client-server application more reliable than a two-tier one?

Question

Software design

Which architecture is faster three-tier or two-tier?

Answer 1

Um ... why is there one question in the subject of the question, and another in the text? Is it a trick to ask 2 different things in one question?
From a user or developer point of view?
In a particular case, when using scaling, a three-tier structure will be faster for the user, due to load distribution.
I will quote the esteemed sim3x

Who said what is more reliable?

Answer 2

I know fast, efficient, super-reliable, killable only in the event of an atomic bombing, applications built on the same level without templates, guides, patterns and unit tests, and I have seen programs where everything is in feng shui, but remains a glitchy Mr. .
The problem, apparently, is not in the architecture, but in the minds of the developers.