Summary

SEO Copywriting is good when:-

1. there are not many search terms to target
2. the search terms are on the low to middle end of competitiveness
3. money isn't a problem, or if it is your own website
4. you don't mind the text on your pages being frozen (if money does matter)

Otherwise, 'search engine friendly' techniques should always be done as a first measure, and real search engine optimization should be done for the search terms for which 'search engine friendly' techniques are unsuccessful.

NOTE: Competitive search terms are not necessarily those where millions of results are returned. They are those where people are competing hard for the top positions. There's a big difference.