There are a few people out there self-dosing with snake venom. The posted article is based on a study on the blood of one of these guys, Tim Friede, who has developed very effective antivenom in his blood after 20 years of self-dosing with a diverse array of snake venoms.
Vice did a few documentaries on Steve Ludwin, who is also self-immunizing. In one of these he answers questions about how he began and his motivation for doing what he does. In addition to producing anti-bodies he also believes that snake venoms have medicinal and anti-ageing properties - but these beliefs do not appear to be supported by any animal-based data as far as I can tell: https://www.youtube.com/watch?v=AcbqB0pFRPA
Self-dosing with snake venom is not something I would recommend. Generally a bad idea. But it is interesting to see the results and to learn about what motivates someone to do something like this.
Snake venom gram for gram is a lot less toxic than some other substances we consume. (For fun, look up how much a lethal does of caffeine is) I can understand the logic of testing snake venom for medicinal properties, but injecting yourself with it as your test is the jump over the line to stupid.