Where I grew up, my father built his own home. In our backyard, it overlooked a 90' escarpment down to an oxbow lake that used to be the river. In the 30's, the WPA cut the lake off from the main river channel and built a road across the open horseshoe end. We lived on the high bank of the old river. My father built steps down to the bottom of that escarpment, using pretty much the same techniques you used on your driveway spur, minus the geogrid... it just wasn't available or even known about back then. Anyhow, he would drive around town and pick up pieces of broken concrete sidewalk when they were being replaced. The rough broken edges look a lot like a natural stone material. He had to start from the top and work his way down, which isn't the best method for building stairs. So he did it in manageable, 20' sections or so. He'd cut the hill to the right, build a spur like you have, then work his way up. Then he'd make a switchback at the bottom of the spur, cut the hill to the left and repeat. There were 7-8 switchbacks and about 150 steps down to that lake.
The only problems were leaf litter and dirt that would come down the hill and cover the steps and landings each year. So it was a spring ritual for dad to hand me a pointed trowel and a bucket, and I'd have to scrape the dirt and dead leave, full of great worms for fishing, out of the corners and steps. It would take a day, but worth it. If you didn't keep up on it, the steps would be overrun with debris from above in just two years or so. We sold the house after he passed away around 1995. I go ice fishing at that lake every winter. There is almost no visible traces of those steps now. They are completely covered by forest floor debris.
So, from that experience, I'll ask you if you've made provisions to keep uphill debris from coming down onto your spur? Just watch it over time and keep a leaf blower handy and don't let anything build up on there and rot into soil or in a surprisingly short couple-three years, you'll lose a couple feet of area on the uphill side.
