You definitely can, the principle is still valid. Anyway, Route53 is extremely cheap, less than a dollar for a million queries per month, is very reliable and it integrates very well with the other AWS services, so it's definitely worth the price, IMO. What alternative services where you thinking about?

I already have a domain registered on dreamhost and I didn't want to change nameservers. But reading about the alias concept and its cheapness, as you said, I think I'm going to migrate to R53!

Thank you!

DNS, SMTP and such are boring services! R53 is robust cheap and doesn't need maintaining so .. go for it!