It depends upon the context.
If someone who is not educated or has a very very basic education and is coming from a very rural area where English (or even Hindi) is non-existent, then they should be given the opportunity to succeed in life by using their regional language.
However if a person is well educated, then they should be comfortable with English in general.
In 1:1 conversations or in smaller groups it's fine to use the local language (as long as you know all the people involved know that language).
But in larger groups or smaller groups with impactful people (e.g. potential/existing customers/stakeholders) one should be able to use English in an understandable manner.
The fear of being unable to speak fluent English restricts people from speaking in understandable and simple English; which many people around the world not having English as their first language do and they are fine with it.
But somehow we are obsessed/pressurised with speaking Fluent English only.