You ask "are schema needed". The simple answer is no. The more complicated answer is that it depends on your situation and what schema you are asking about.
Address: Google has a number of ways of understanding where a business is located. They have been parsing simple HTML addresses for years and can read it easily from a single location website with or without schema.
Schema address is a "clarity" signal not a ranking signal. It is "needed" if there are any situations in the real world that would confuse Google.... has the business moved, are there multiple locations owned by the same company that might confuse the machine and be conflated? If so then it is needed. If not then its a nicety that as was pointed out is nice to have but not critical.
Schema though isn't limited to just address. It can be used to
highlight your own reviews (not reviews from 3rd parties), delineate your services more clearly to Google and even provide Google direct information about events or
scheduling options that you might be offering. All of those might (operative word might) provide Google with additional information that they will share in your knowledge panel and that would improved conversions (but not rank).
The statement that G+ doesn't impact local, though, is not entirely accurate. I have tested and can verify that when done right a well run G+ campaign can impact local rank quite a bit. G+ has a verified relationship to the local business and if you can create a G+ account that has active increase in real followers, that actively comment on, share and plus your content and do so over time, it can increase rank and local traffic.
It is no easy task on G+ to be successful using it this way, but it is possible and it can in fact impact local outcomes.
