Glad you found my entry on SMBC.
I suggest you GO FOR IT. If you are used to mousseline, silk meringue is its cousin. The addition of creme anglaise makes this buttercream richer and tastier, closer to a buttercream made with egg yolks.
All of Rose’s SMBC variations are delicious (you can tell it is her favorite frosting by the number of variations she lists!!!). My personal prefered ones are the caramel variation (caramel is a clean taste that intensifies the flavor of vanilla on creme anglaise), and recently I made a pistachio variation (by using pistachio creme anglaise).
Mousseline is a cleaner taste, almost tasteless, which goes well when you just want to flavor it with liquors or fruit conserves, so these delicate aromas don’t get lost. Liquor flavor on SMBC gets lost. Citrus flavors on SMBC are great (has to do that citrus balances the extra fat texture on SMBC).
If you heat the sugar syrup a degree or two higher, you will get EXCELLENT stability on SMBC, too.
BTW, frozen SMBC tastes and feels just like ice cream, often you will see me scooping SMBC onto my ice cream dish.