Looking forward, unless EcoFont has a patent on swiss-cheesing fonts, one could potentially make swiss-cheese versions of the existing fonts in LO.
That would be very good to have on LO for anyone that wants to save ink and use whatever font they like, but will be not be part of version 3.5?
As for merely saving toner/ink when printing, it appears that someone did some testing and found that some fonts (e.g. Century Gothic) will save more ink per word than the EcoFont. http://www.treehugger.com/sustainable-product-design/century-gothic-saves-more-ink-than-ecofont.html
The ecofont website has tells the advantages of their fonts: http://www.ecofont.com/en/products/green/printing/saving-printing-costs-and-eco-friendly/why-ecofont-saves-more-ink-than-century-gothic.html -- Thanks