Lights on or off is a personal choice, however if your have six or seven hundred lights flashing at once it may be a little over the top.
If you are decorating your tree using multiple sets, say 3 sets of 200 lights, use the first set to cover the bottom of the tree, the second set to cover the top and have these two sets on steady. Then lay the third set of lights so that its scatters over the entire tree, have this set flashing.
Alternatively you can use the popular twinkle lights as the base lighting for you tree and have this on steady, and then lay a set of feature lights over the top, put a link to pinecone lights here and have these lights flashing.
https://www.christmaskingdom.com.au/product-category/christmas-lights/christmas-lights-fairy-lights/