Hi Shugdentruth
Yes, Dzambala's practice is a very good one for wealth also; actually, how Dzambala helps is at a very profound and meaningful level. He helps us most by helping us to open our mind and being more generous - that is the greatest and best cause to generate wealth. So whether we receive the wealth or not, the practice helps us become more generous, less stingey. Then, whether we have wealth or not, we are not grasping and as attached to money, and we are happier beings.
I believe that the Dharma protectors' practice is slightly different with regards to wealth. They help to bring us wealth in relation to our Dharma practice. In other words, it is a way of clearing an obstacle to our Dharma practice. For example, we may be so poor or in such need of money that we are forced to go out to work very tedious jobs and therefore not able to dedicate as much time to our spiritual practice. A Dharma protector like Dorje Shugden can help us to find a better paying job, so that we don't have to spend as much time at work, and can dedicate more of our time (and eventually even money) to Dharma. He does not grant us wealth just for the sake of wealth but so that it can aid us in our Dharma practice.
Also, there is a slightly different way in which these two practices are presented. Dzambala is a yidam practice, which is a deeper, meditational practice - the effects may seem to take longer to come but they are profound changes in our minds that are everlasting. Dharma Protectors are "closer" to us and the effects of their practice may seem to be quicker, but they may not be the end all. i.e. the wealth, resources or good conditions that come from a dharma protector's practice is not the end and that's the end of the practice. It is to create the necessary, comfortable conditions for us to be able to practice Dharma and gain the mind transformation and benefits of "deeper" practices like the yidam practices. It is like this: yidam practices become the central meditational focus of our practice and we strive to become of the same enlightened mind as our yidam; the Dharma protector practices are a supportive practice that pushes us towards the direction of the yidams.
Now, something special - Dorje Shugden is both. He manifests in this form as a Dharma protector but remember he is also an emanation of Manjushri / Yamantaka who are very powerful yidams too.
Oh no, beggar has gone off on a tangent!
Good luck!