The same question occured to me over the past several months while reading the freebie Olive Leaf Book MH gave me with a purchase :) The name and author escapes me right now (Walker?) but it's a small book with fine print. I tried the method described in this book on how to make my own extract, which is basically an infusion (hot tea) done over the period of at leat 48 hours brewing the leaves in simmering water. This was discussed in the forum here, and MH chimed in with kickign up this method with his own tips, so you might want to check the archive. With this method of extraction, one must of course then drink this extract/infusion/tea in order to put the benefits of Olive Leaf to work inside their body. .
I may be wrong but the powder is just the leaves ground through a blender or special grinder, so powder is really powder of leaves. It seems to me that the alternative of taking Olive Leaf by swallowing the powder puts the onus (for the process for extracting the beneficial ingredients) on the functioning of one's internal body, digestion & metabolism compared to the tea method. In other words, which method of extraction is preferred? Extraction by hot water in a crock pot or powder in your body? Either way the body will need to put this extraction to good use.