Money in Morocco

Get your local Moroccan dirhams from an ATM once you get there. Don’t bring cash with you to Morocco (unless you have a desert tour company that wants to be paid in U.S. dollars, like ours did), and use dirhams once you get there.

I was there in January. I hadn't realized the dirham is "protected", as I prefer to have about $100 in local dollars prior to arrival anywhere outside the US. I'm in the minority with this! I also know fees are higher but purchased some at the airport from an agency vs an ATM. Some hotels and restaurants appeared to also accept USD or euros.
I was with a group of 12 on a tour. The guide was helpful along the way with stopping at ATMs she knew reliably worked- even still, sometimes some in the group had their cards rejected. Cash was often needed in smaller towns and rural areas, depending on your itinerary.
(You're going to need cash/coins for toilets, every- where!)
It's a fascinating and beautiful country, have a wonderful trip!

You can't get or spend dirhams outside of Morocco. Get some from an ATM at your port of entry, and reload as required. ATM's are everywhere, but some are finicky. Using euros will cost you a lot in hidden exchange rates. Its always cheaper to use the local currency. Just think: in your hometown, would YOU rather be paid in Euros, or in your local currency?

Ditto the need for coins. You will need them for bathrooms, tips and many purchases.

THANKS for all the advice

Beware, and this may have changed since I was there, but there were no currency exchange places behind security in the airport in Casablanca. I didn’t know this and got stuck with a bunch of dirhams as I wasn’t going back through security again.

We were in Morocco in February as part of a tour group. we were able to get dirhams from our bank at home before our trip. I am sure you could do the same.
We found that some atms in Morocco at banks would work with our cards and some didn’t. Usually your hotel or your tour leader will let you know which banks to try. We also talked with other tour members about which are successful. We found that master card seemed to work most often. We had a bank card from our local bank that was associated with Barclays that seemed to work well. Be aware that many Moroccan bank atms will not work without a Moroccan bank card. We found that getting money in Morocco was easier than we thought.
Another tour member traveling with us had a difficult time because she had relied on changing money from dollars to dirhams. She wasn’t able to find money changers at the airport at Rabat and had trouble changing money throughout the trip.

I should add that dollars were often accepted and they seemed easier to us than euros.
Morocco seemed to have a successful economy and did not seem to us like a third world nation.