So, TIPS is just one of the available clearing mechanisms available for the SEPA Inst scheme. (The other one is RT1, which is live a little bit longer)
Currently, there is no "regulatory forced" interoperability between RT1 and TIPS, though the 4CB are discussing it. (Esp. since RT1 is a private clearing mechanism, while TIPS is the one operated by the 4CB)
And, regarding fee: You are wrong - depending on the local jurisdiction (esp. consumer rights), a bank may for sure charge for processing SEPA SCT Instant messages. Over here, SEPA Instant transactions are around 0,50EUR - 1,00EUR, currently; some are also offering them for free.
DISCLAIMER: Lead Payment Engineer at an European Challenger Bank, i'm implementing that stuff in the backend, i'm mainly talking to our central bank.