I have done a lot of high alpine hunting and guiding for tahr and chamois. Over the winter I sometimes carry the smaller instep crampons just in case they may be needed and have occasionally used them for steep slippery grass slopes, but never deliberately used them to access steep icy area's - if you need them for that, then you need full crampons fitted to crampon compatible boots. BUT I have used them to cross steep shingle and scree slopes late in the day when the sun has gone off them and the light snow that was easy to walk across in the morning has now thawed somewhat and then frozen proving treacherous for the return to the hut. And as said previously, only use them with either an ice axe or trekking pole strong enough for the task, and adequate knowledge of how to use them correctly.
If you go for full crampons there are a number of good quality lighter models available both for rigid or flexible boots. And you will definitely need a good iceaxe to go with them. And most importantly you will need some good instruction on how to use them and how to self arrest should you fall. If you are going to that extent, then probably pay to have a good mate with you as well who is also suitably trained, and then you need a decent rope and know how to belay.......the list goes on.
