The tips are very useful who want to learn a new language. One should not just read and leave. But it is always good to recall the words which were read. Using spaced repetition is another tip that helps in learning a new language.
Learning of more and more languages can only benefit the learner and cannot be proved as detrimental. It all depends upon the learner how to keep the languages in practice or else one will definitely forget them language.
A new language helps in communicating with others. Just think of coming to my state where Telugu is spoken and you communicate in Telugu with the local people for anything, you will get immediate help especially in the markets. They a language unifies.
I know Sunil you are adept in many languages. That's because you are a globe trotter who love to visit places, learn their culture. That has many advantages. No place in India will look new and strange to you.Kudos to you.