I did a B.Tech in Chemical Engineering from IIT Bombay. Per feedback from my father about his MBA coworkers, I decided not to do MBA immediately. I worked for 3 years before getting into Jamnalal Bajaj in the then Bombay for a Masters in Marketing Management post graduate degree.
To me, the purpose of doing an MBA was very clear: To earn a qualification in my chosen field of sales and marketing.
The result: Engineering taught me how to solve problems. MBA taught me how to judge which problems are worth solving.
UPDATE DATED 21 APRIL 2020:
Stumbled on to my 5 year old answer. Making some edits and additions, basis new learnings and recollections of old learnings.
As I said before, in MBA I learned about which problems are worth solving.
In addition, MBA also taught me how much effort should be put into solving the problems judged to be worth solving.
I also realized after MBA that you can gauge the essence and directionality of almost anything in business by reading a few Twitter Threads or articles.
If you can’t, you won’t even after reading 100 books on the topic. In other words, the marginal utility – extra knowledge and insight that can be gained – of all that extra reading is negligible. Of course, this is not true for certain complex subjects. But those are probably above my paygrade and I won’t go near them anyway.
While the OP is not about MBA versus Engineer, I feel that a comparison will help throw more light on the topic at hand.
In the following illustration, Engineer would tend to demonstrate Goofus style of deterministic reasoning whereas MBA would tend to demonstrate Gallant style of probabilistic reasoning.
Source: Prediction. Goofus. Gallant. A Failure, But Not Of Prediction | Slate Star Codex
Nothing right, nothing wrong, context determines which style of reasoning is more suitable.
But one thing seems clear to me: When combined with luck, street smarts, and a strong sense of intuition, the Gallant style fostered by MBA will improve chances of success as an Entrepreneur.