Sorry. Just saw - “without valve or thermometer” - not as useful this way. But, you could use it to heat sparge water and transfer it to an igloo cooler for mash and sparge. 8 gallons is on the small side for a boil kettle when doing a full 5 gallon all grain batch - it can be done, but it is tight.
I think the pot and wortchiller are the two best places to spend money when starting - two crucial pieces of equipment that make your brewday much easier and they last forever.
One other thought - a great place to save money is fermenters - buckets are perfectly fine. Many people prefer them over carboys. What are you paying for that is extra in the deluxe starter kit as opposed to a more basic starter kit. Might be able to use the difference to upgrade somewhere else.
Just a thought. Either way you are on the right track.