There is a trade-off between risk and speed, sometimes. Over my years training on the Dartmoor ranges, my boots have progressively got lighter and less sturdy. From the good old Pro boot developed after the lessons from Falklands, to current ones designed for Afghanistan. When up there in civvies, I now tend to use Roclite 325s for a great compromise on support and speed. I can run in them for hours almost as easily as my fell running shoes and yet they are above the ankle boots.
Same in Snowdonia or anywhere. If I'm just walking or scrambling I'll probably use my La Sportiva Guide mountain boots. If I'm running the same route I'd go for my Roclite 325s or even my Asics FujiTrabuco fell running shoes. Similarly, my waterproofs would shift from Paramo smock to a 2.5 layer ultralight pull-on, etc. Yes, there is a greater risk, but it is a conscious trade-off for a given purpose.
And if I'm walking in then guiding a client up an easy climb I might well wear my Scarpa Gecko approach shoes.
Or perhaps I'm just sticking to the main paths up Snowdon in decent weather and I might not bother to change out of my North Face Hedgehog walking shoes.
One thing I've found in years of leading and instructing is that the biggest injury factors in shoes/boots are a really soft sole, insufficient tread, and slippery rubber. The first two are typically due to people wearing trainers and the latter is usually brand new boots. Soft sole can lead directly to toe injuries in rough ground/pebbles, and all can lead to potentially dangerous slips. I now worry more about soles than I do ankle support in normal hillwalking.