To justify a compressor there really needs to be the need for air and the availability to shoot. If it is difficult to find a place to shoot or limited available time, it might be more economical to find a fill station. We as shooter see the need for the compressor, and I got tired of going to the paintball range every weekend to get my tank filled. It was only open on the weekends so it also ate into my shooting time. I think the compressor comes later once you have "swollowed the hook" and KNOW you want to continue to shoot PCP's. During the summer months, I shoot nearly every day, so it makes sense to get a compressor. But If I was limited to "shooting at a range" on the weekends, not sure it make sense unless you have an hour drive to get your tank filled. So, yes i would get a compressor if you want to stay in the PCP hobby, but you might want to make sure by purchasing that nice rifle and tank set-up first. Once you tire of going to the fill center, then you get the compressor.
Unless you have easy access to air, you probably won't stay in the hobby. This was a good post, Norman!