A reimbursement claim can take longer to process than a cashless claim. For a reimbursement claim, you need to ensure you collect and submit all the documents and bills related to your hospitalisation. On the other hand, in a cashless claim, the empanelled hospital will do the job of sending your documents and bills to the insurance company, and the claim will be settled with them directly.
In a reimbursement claim, you have to wait till you get your money reimbursed from the insurance company, whereas in a cashless claim, the insurance company will pay it straight to the hospital. You will only have to bear the expenses that are excluded from your policy or are over your sum insured.
Since your insurance company does not have a tie-up with the hospital, your reimbursement claim will be thoroughly investigated. This may further delay your claim settlement. Cashless claims instead tend to get settled faster and in a hassle-free manner.