VW Cloud Subsidiary - Software Engineer role

I recently received an email for Software Engineer role for VW Cloud Subsidiary something they collaborate with Microsoft. The assessment test went well and then HR called me and explained next steps and started low balling (I am assuming she was doing it as I work with Expedia and she assumed I must be desperate). Low ball to an extent that she offered lower than what I making today, told me no bonus and no stock option some lousy benefits she kept focusing on. I told her I am expecting incrementing of 20% and can settle to 15% but no less. She said we can go forward you may or may not get that number. I said if you are guaranteed that number will not change I will pass the interview. To that she switched her tone to 'may be we can change' so I agreed to interview. Have any experienced anything similar? Does it make sense to interview?