The last 'wood' deck I built had the fit and finish of fine cabinetry the day I was finished.
Six months later it looked as though I slapped it together using nothing other than a chainsaw for the cuts. Wood shrinkage, warping, cupping, checking... with exception of one area that was a different batch of lumber. $7K in materials and a ton of work is now an eyesore to me. And yes, I know how to choose heartwood and which side of the board goes up.

Lumber is just crap now.

Depending on your soil those blocks may work just fine. Sandy, rocky soils would be best. Expansive soils like clays would require piers.
Good luck with the project.