The meaning of this passage is that those who obtained benefit during the Former and Middle Days of the Law received "conspicuous" benefit, because the relationship they formed with the Lotus Sutra during the lifetime of the Buddha had finally matured. On the other hand, those born today in the Latter Day of the Law receive the seeds of Buddhahood for the first time, and their benefit is therefore "inconspicuous."
The Writings of Nichiren Daishonin, page 474
The Teaching, Practice and Proof
Written to Sammi-bo on March 21, 1275
Those who strengthen their faith day by day and month after month are genuine practitioners. Our daily practice of gongyo, therefore, is important, as well as attending meetings every month. We must not let our faith grow weak. We must make it stronger today than yesterday, stronger this month than last. Buddhist practice is a succession of such untiring efforts, the ultimate goal of which is attaining the summit of Buddhahood.
Knowledge gives rise to wisdom. If you like, knowledge is the pump; wisdom is the water that we get from the pump. If we can't obtain water, the pump is useless. At the same time, without knowledge, without the pump, we won't be able to obtain water.