The point about seasons is not about when you stay, but about how many points you would get for the same MFs.
If you have a Gold season in Vegas (I think the numbers I'm giving are for 2BR, but it works the same in any case), you'll get 5000 points for about $980 or so.
If it's a Platinum 2BR, you'll get 7000 points for the same $980. More points for same same MFs (and likely a bit higher on the purchase price), so this adds up over time.
So, two 5000 point contracts gives you 10000 points for about $1900 in yearly MFs. 14000 points can be had for the same MFs.
As someone who has two 5000 point Gold weeks in Vegas, I know well of what I speak about this mistake
And, to your point, we've used ours for Bay Club quite a few times with no availability issues.
Cheers.