This type of enthusiasm refers to an unfortunate tendency to plunge into every task with little or no forethought as to the consequences of one’s actions, including how a task would be best approached, safety considerations, economy of time vs. money, etc.
‘Enthusiastic’ workers, particularly in combination with sub-standard training and supervision, can have a potentially disastrous effect on your project or business venture, especially if the engineers, or anyone doing delicate work, is of this ilk. For example, your Chinese counterpart may proudly point to the frugality of a particular approach, system, etc while completely failing to take into account the downsides of the cheaper approach.
Saving money for its own sake can still be the primary goal of some Chinese businesspeople. For example, inadequate lighting may be rationalised with the explanation that good lighting ‘wastes’ electricity, and Chinese workers can manage perfectly well in a sub-standard working environment. Or inappropriate maintenance (e.g., harsh chemicals on delicate machinery) may be a demonstration of thrift and efficiency to your Chinese counterpart, not a dangerous and/or ill-considered practice that could irretrievably damage the project.