This is easy to explain. Main premise of agile is spending a lot of effort on improving the process. These are the standups, demos, retrospectives, etc. It is

This is easy to explain. Main premise of agile is spending a lot of effort on improving the process. These are the standups, demos, retrospectives, etc. It is no wonder you get more done if you cut the effort. You are coasting on past improvements. This is only going to work for a while until your performance starts to slip because the team stopped correcting and improving. Spending time on improvements is important for other reasons. If your team spends 100% of the time on project work it is inefficient by definition (though not very intuitively, but see constraint theory). Spending time on improvements creates necessary flexible buffer. This is an alternative task when there is shortage of project work or it can be temporarily cut if there is too much project work.