Agile project management means responding to changing circumstances – it is characterised by its flexibility and speed. It is questionable as to whether it can be used in all circumstances, but it is useful in disciplines such as IT.
Agile projects tend to be smaller, shorter, the team is more capable and because there is nowhere to hide, the individuals become more capable. It can also create higher staff turnover because of the personal accountability and peer pressure that agile project management promotes. Sponsor involvement is often much closer.
There is resistance to the approach because it can be fairly imprecise in terms of time and budget. It relies heavily on trust over formal governance structures.
However, an agile culture can grow organically. Once success is realised it is often adopted elsewhere in the organisation.