Honestly it depends on your certification. If it's CSCS, NASM, or NSCA, then perhaps....anything else isn't really well respected anymore (at least not where I'm from - all the PT clinics that have personal trainers require one of the aforementioned 3 certifications because they require lots of anatomy and physiology knowledge, and an educational background that other certifications do not).
It definitely won't hurt your application, and it could possibly help (showing you have a strong background in fitness, take health and wellness seriously, understand ex phys, etc.). But, PT and personal training are very different, and are targeted at different people. It won't replace the PT observation experience, but it could potentially help you get a slight edge if you're competitive in other ways too.
Some PT schools (i.e. NYU) even require their PT students to become certified trainers to help pay for school 🙂