Not at all. This "DNS Cache" to which you refer is how DNS fundamentally works, and is the manner in which DNS records are updated. The more, the merrier, in this scenario.
Most of the free or nearly-free web hosting comes with strings attached--adverts and annoying popups. By becoming your own webhost and using DDNS to bind your domain to your dynamic IP, you avoid all of that. Additionally, you gain the advantage of binding your domain to more than just a website if you so choose. All without the hassle of adverts and the unprofessional spam overhead it adds.
