In some companies, "If the weather is looking pretty grotty", planning for a second alternate is compulsory.
That's true but that plan includes a
choice of alternates, so that you have more than one option available if your destination is below limits. What it doesn't necessarily do is give you the ability to go to one alternate then divert to somewhere else from that original alternate.
In real life it may not take much 'extra' fuel to give yourself a nice selection of places to go; you're increasing the size of the area inside which you can reach another airport. If you wanted
sequential alternates, it'll take a bit more gas to achieve...