It does the multimedia indexing so it would affect their multimedia services. Given how absolutely useless I found their multimedia service I certainly don’t miss it.
Even with all the services disabled the indexer still runs. Synology support have said they may look at changing this so it only runs when ones of the services that require is enabled.
Just rename the file as I did and make sure that everything that you need is still working. If not you can simply rename it back.