As we’re talking about France I suggest the French legal framework. Assuming you actually feel the need to be “guided” as in shown the way down rather finding you own route down:
If you want to go ski-mountaineering (ski alpinisme) in high mountains outside a ski resort you need a mountain guide.
If you want to ski down from a lift off piste in a ski resort then you need a moniteur hors piste.
If yo u want to ski down from a lift that’s considered haute montagne (Vallée Blanche) then you need a guide or a moniteur-guide.
The divisions between the different activities are flexible to some extent but jurisprudences are there to tell people when they are stepping out of their domaine de competence. If you want to ski down that face in Tignes then the obvious person to hire is a fully qualified moniteur de ski. It’s very much a part of the ESF’s regular business. If you want instruction during the descent then ask the moniteur for for it, if not you’ll get a few tips along the way. It’s a service, you make what you will of it.
The reasons for hiring a moniteur hors piste depend on the client but people I know who use them simply want to be shown around the best hors piste runs in an unfamiliar resort. Thus benefiting from the moniteur’s local knowledge of runs, snow conditions, objective risks and difficulty. It’s not a 100% guarantee of safety (as today’s unfortunate accident shows) but it does mean you’re less likely to:
-ski down the wrong couloir
-misread the snow conditions and avalanche risk
-attempt something beyond your ability (junior is really rigorous about assessing a client before doing anything difficult even on piste)
-get lost
-ski over a cliff
-etc.
Edit. for the IGN maps you have to go into the normal Geoportal site rather than the risks one, Jamba.