No there is no downsides of having the MIPI license free of charge.
These IPs are still fully supported and will still be under development for new features. For example, Versal devices will be supported.
As per any IP, if Xilinx was to depreciate the IP, there will be a Discontinuation notice and the IP would still be supported for a year. But again, this is no a plan of record, the MIPI IPs are an important piece of Xilinx offering.
So as far as I am aware, there are only the good side of not having to pay for the license
Florent Product Application Engineer - Xilinx Technical Support EMEA **~ Don't forget to reply, give kudos, and accept as solution.~**