For 2018 the India goods trade surplus with the US was $21 billion ($33.5b in US exports to India; $54.3b in India exports to the US).
US exports to India climbed from $21b to $33b over the prior two years (2017 & 2018). That's a nice increase of $12b or 57%; their exports to the US increased by $8b over that same time frame.
To put that into context, US exports to India will match US exports to France this year approximately, so it's already a serious export market for the US (and 50%+ larger than US exports to Italy, which is the 8th largest economy). Importantly, India has serious economic growth and a likely high long-term growth trajectory, whereas most of the top 20 economies have had very little or zero growth the past decade plus. If you're the US and you're seeking export growth, India is one of the best options.
The primary benefit to maintaining a good, equitable economic relationship with India, is that they're likely to have a very large economy in the near future. Even though they will remain poor per capita for a long time, they're almost guaranteed to become the world's third largest economy behind the US and China in the next few decades.
In terms of economic output they passed France this year and will soon pass the UK (within 6-12 months if they haven't already). That puts them #5 behind Germany, which they'll plausibly pass in six or seven years. 20 years from now when they have a $8 or $10 trillion economy, as an American, I'd prefer that the US have a reasonable economic relationship with India that benefits both sides. In the future they will probably be a very important market for the US, so you should try to take care of the relationship today.