I think you were given bad advice. As already mentioned, a 4K Blu-ray player can work with non-4K televisions or projectors. The one good reason for not buying a 4k player is if you are convinced that no 4K disc of a movie you like will ever be a worthwhile upgrade from the Blu-ray disc...
I'm not sure it's his worst film but It's certainly one I've never liked. However, in view of RAH's very positive review of this 4K disc, I'll have a second look at the Blu-ray disc to see if I want to spend money on an upgrade.