Irish answered your question well, but just to be clear... right under the Starpoints it says "Starpoints Earned YTD with your card," so that is everything earned since January 1st as of your most recent statement (it's not in real time). Amex sends your new earnings to your SPG account when your statement closes and they appear usually within 24-48 hours in your SPG account, and are then added to that number that displays in your Amex account. At no time do you have a pool of points sitting with Amex like you would with Membership Rewards points.
Agreed, not wise at all. TPG's valuation is actually up to 2.7 now and even that is very conservative. With things like the Marriott exchange rate and 5th night free, it's easy to get twice that or more! I could see doing it if you had points that you knew you would probably never use though. Getting 1/3 or less value is better than none. The issue with that is that you usually have to transfer in even increments of thousands so OP would need 1,000 SPG points to even get started.
If the 2-5-10 are just from the yearly SPG card bonus towards elite status and you really don't stay at SPG/Marriott/R-C properties, I'd just move 1000 Starwood points to another rewards program. Also worth hitting up AmEx retention.