Actually, Roth earnings are tax-free if distributed when the account is at least 5 years old
and due to one of 4 special purposes:
*owner over age 59 1/2
*owner qualifies as a first-time home buyer ($10,000 limit applies to earnings )
*due to the owner's death
*due to the owner's disability.
So, distributions of Roth earnings after 5 years for a first time home purchase
will be tax-free and penalty free.
I think this can be an important niche planning tool. Consider a working 20 year old who wants to buy a house in 5 years and has no concept of retirement planning. Parents may choose to gift $2000/yr to her to invest in a Roth. At age 25, it may be worth $15,000. Then, she buys a first home. $10,000 comes out tax-free as a return of principal. The remaining $5000 is earnings and is withdrawn tax free due to the qualifying first time home purchase. Not a bad way to do it.
Check out
Fairmark's discussion of Roth distributions