From the F2P perspective, most players are afraid that new team instances in the future will reward better ninja tools.

These essenses are limited for F2P players, if you use them now, you will have none for the better tools in future.

As a F2P, it is essential to min/max our resources and wait for these better tools.

You just need to weigh the short term gains in power vs long term gains.

OFC this post does not apply to paying players.

Just my 2cents worth.