The raw materials are fairly cheap to buy at embark, and because you can smelt the alloy directly from the ore and there are no intermediate steps like for steel it's both work- and fuel efficient. You will have a minor initial investment (the first fuel which you can also make yourself from a dismantled wagon, building smelter and forge). After this is done, your investment for every set of 4 bronze items is:
3x bituminous coal -> 2 net fuel
2x cassiterite, copper ore, fuel -> 2 bronze bars
4x bronze bar, fuel -> item
Which comes down to 33 embark points and 9 tasks. This is really quite cheap, and taking it with you for all bronze items you will ever need before switching to steel is realistic.
*
Compare this to the cost of manufacturing each set of 4 steel items right from the start. The process is:
8x bituminous coal -> 2 net fuel
4x ore + fuel -> iron
2x ore + 2 fuel + flux -> pig iron
2x iron + pig iron + 2 fuel + flux -> 2 steel
4x steel + fuel -> steel item
144 Embark points and 20 tasks per set of 4. If this takes up too much labour, it gets even more expensive:
6x bituminous coal -> 2 net fuel
2x ore + fuel -> 2 iron
2x iron + pig iron + 2 fuel + flux -> 2 steel
4x steel + fuel -> steel item
178 embark points and 14 tasks per set of 4.