I rode foils only a few times, so these are really my two cents. The problem I experieced with foils in very light wind when they suddenly fall. In my home spot, in very light wind days, sometimes the wind really goes to zero for 1 minute or so. When this happen, both foils and inflatables suddenly fall. In this cases, my inflatable ... falls directly into the water with no line tangling and I just have to wait for a gust to relaunch (when possible, that means about 7 knots for my Core 17). When a foil falls with no wind, being very light, it's common that its lines roll over it and became completely tangled. At that point, it's not that easy to relaunch.
The other big problem with foils in very light wind is when the wind completely stops. With an inflatable, you just get your kite and swim attached to your little floating boat. With a foil, you have 20 sqm of tissue to carry home with you!
But, Pmaggie,.... Which foil?
You tell us which inflatable you use, but not which foil you have used...