[Skarg]

They aren't hugely lethal, used simply as written in Basic, but it depends on the circumstances, and how you use them and other rules.

I like to track each bleeding wound and then a large battle with many more bleeding wounds than people with first aid, can become interesting. Especially if you add some spice rules where some wounds bleed more than others, or are difficult to stop bleeding on. In real life, internal bleeding can take more than simple first aid to diagnose and stop.

And if you want even more lethality, you can use and develop the infection rules...

If you want less lethality, you can make an easy "stop bleeding" technique available to people without full First Aid skill (which of course should be at least a little less effective than actual First Aid skill at stopping bleeding, but can be given to semi-competent grunt types). Bad rolls on that though may lead to infection... :-)