Cons could include difficulty of possession for countries, and the likelihood of throwing up without 3rd party medications.
The reason for using sn is that there are (a none or very minimal after effects of sodium nitrite if failed (b it takes roughly 30 minutes until passing out, with only mild discomfort (c may not be the same for others', but the ease of use. After fasting, simply do a quick calculation of grams, then mix it in a glass of water, then drink. There are extra things you can do to increase efficiency, but they are not necessary to the method itself. Hanging requires tying knots, finding specific arteries, looking at different types, etc. Other methods require a lot of research, which sn may or may not depending on the country and circumstances the person is from. There's not many truly easy methods, asides from possibly jumping.