One other use for TPs is in bad location provences where you want an eventual colony but cannot afford it now. Place the TP, which gives you 10 pop. then when you go to colonize it, do it as fast as possible. that way the negative growth will only eat into the extra 10 pop you have, which means you will only need to send 7 cononist instead of 8. It uses the same number of colonists (7+1 trader) but the trader costs you less and usually has a better success rate in those areas. If you are going to colonize higher you may be better with the original being a colonist for the extra pop, but at 700 you can do other things to offset the negative growth, like a govenor or a manufactory. Plus the pop will never drop below 700.
