Very logical ytm/spot rate question investing, something, understand, buying

jlg1982

If I understand correctly YTM (or as a matter of fact also spot rate) is a rate that sets the present value of cash flows equal to price of security. Correct?

So here is my question:
As an investor why would I invest in something that has NPV=0? I do not realize any gains/losses investing in it. In other words, if I pay 94 today and receive 100 a year from now, the 100 a year from now has only a 94$ buying power.

Is my understanding of YTM/spot rates correct. I am afraid I may not have understood YMT/spot rates correctly.