Is refinancing for the equity a good idea?

[Travis Blaize]

So I had a question about refinancing your property to get the equity that you had in it. I was speaking with a colleague today, and he told me how he had purchased his house for 150k, and he had it appraised and it was worth 200k now. So he was going to refinance and take the 50k worth of equity he had accrued and use that 50k to purchase rental properties.
He said that with the refinancing and having a better interest rate that his payments wouldn’t change so month to month on his current house would remain the same mortgage payment.
My question to everyone is, is that a wise investment strategy in the long run, because it seems to work out in the short term with being able to purchase rental properties that you would possibly generate monthly income as well as equity from those properties. Any thoughts and comments would be appreciated!!!! Thanks in advance