HELOC for debt consolidation

We are planning on using a Heloc to pay $58,000 dollars in credit card debt. It will bring the $1,900 dollars in minimum card payments we pay monthly down to about a $630 dollar Heloc payment. We then plan to pay an extra 600 dollars most months toward it. ( other than Decembers for Christmas and Augusts for back to school), so 10 months a year we are paying an extra 600 on it. Our youngest just went to Kinder so we no longer have daycare expenses which frees up some money to snowball or avalanche the debt. If we are not planning on selling our home for at least 6-7 years or longer, is there a downside I am not seeing? It will be all the allowable equity for the Heloc. We have stable jobs and income. Our after intro variable rate is the 8 percent range, but our credit cards are all over 20 percent interest. This is our first time with debt. We honestly couldn’t afford childcare, but couldn’t afford not working either.