I've some experience of the use of 129.825 which has fulfilled the same role for microlight fields over many years.
Assuming it works out much like the microlight frequency has, monitoring it may be interesting, but is unlikely to have any real safety benefit beyond that obtained from keeping a good lookout when approaching strips (assuming that they're marked on the chart!).
The normal practice when it is used is to make traffic calls, very like US Unicom calls, when joining, leaving, or active within the circuit of a microlight field. It tends not to be used anyhow if there are just one or two aircraft, but is useful when a field is particularly busy or you want to co-ordinate several aircraft (for example when there's a fly-in going on, or as a convenient local formation or display practice frequency).
129.825 also gets badly abused by a few ill-disciplined pilots who use it as a "chatline", to the infuriation of those of us who actually regard RT discipline as a good thing. Doubtless the same will happen with Safetycom, but that is no reason not to have it.
Another use, is when routing close to a non-radio field is to make a courtesy intentions call so that any field traffic know what you're up to. I have on one occasion done this and to my surprise been promptly invited in for a cup of tea (sadly I didn't have time). I know of an instance where a 747 inadvertently selected 129.825 instead of something similar when coasting in off the Atlantic and a humourous airfield owner did the same - although I think that the 400m strip at **** Farm might have been a bit of a challenge and the captain declined.
I'm guessing that's what will happen with safetycom once pilots have got used to the concept. In the meantime, you could do worse than occasionally monitor the microlight frequency - if only to see what safetycom will turn into.
G