I have no objections to stepping stones and pea gravel but always consider maintenance work in your design. I shook my head when I got to this front entrance because there is no way for me to safely line-trim the gravel/grass border. It's asking for trouble with windows nearby.
There must be some sort of barrier between the grass and gravel. So, please consider maintenance work issues when you're designing your garden.
Vas Sladek, B.Sc., CLHT