Assuming I can afford both, are there any advantages of signing a 30 year fixed mortgage over a 15 year one?

Yes. You will have more cash flow💰

 Double the portion of your monthly    payment that goes to interest and the mortgage will pay off in half the time 

I am a huge proponent of the 15 year mortgage. You build up a ton of equity, much much faster. If you do not plan to stay in the home for a minimum of 8 to10 years, then a 30-year fixed is fine. 

The shorter terms with give you a low rates