Actually the UK hasn't discarded it's system, but you've possibly misunderstood what the system is.

Monty Python was rated as suitable for ages 14+ by the BBFC. Some local authorities (which have power over what may be shown in cinemas) banned cinemas from playing it, but buying a physical copy was never banned.

Nowadays there are only a small number of films outright 'banned' by the BBFC, almost always due to rape or torture scenes that don't have appropriate context, and the 'ban' only extends to screenings and to selling physical copies.

Well, reading about "Monty Python's Life of Brian" gives a rather strong message that censoring played a significant role in the UK for that movie. But you make a good point that rather than it being national censors, it was town councils. Not sure if the general public or artistic creator feel that its much of a difference.

Looking at history of censoring in uk, or looking at examples in other countries, is it a productive, effective and favorable method in keeping citizens well-adjusted?

If the films that have been censored hadn't been, I don't think anyone would be directly be suffering other than the politicians who have some of the public screaming at them. However, if there were no censorship, producers would know they could put anything up and perhaps we would get steadily more and more filth on the screen. Obviously that's hard to be sure about either way.

I think the minimal complete censorship they do now (which seems to be entirely sex/violence related) is probably in about the right place - if people and papers on both side are complaining, that's a good sign you might have found the right balance!

I don't think Monty Python (presumably you're thinking of Life of Brian?) was ever banned in the UK. I certainly saw it in a cinema in England shortly after its release. There were a few protests by some religious groups.