I haven’t read the manga, but based on the show, the end is…alright.
The Trigun Maximum manga wasn’t finished at the time the series aired, so their endings are unrelated. The last 4-5 episodes of the anime are complete originals. (There were two different manga series, and I think the original Trigun manga had more of the goofy-villain-of-the-week stuff, while Maximum, which picked up where the first series left off, was more serious.)
Depends on how much effort the average scammer puts into remembering the prospective victims that don’t bite. My guess is that they don’t waste too many brain cells on that.