When I first started reading this post and replies I had similar thoughts as others, this idea is the opposite of using leverage to scale. But I can see how this might be a useful option for people in specific situations, in fact I might be one of them.
Before I came around to understanding how debt can be used as leverage I was paying extra on my mortgage every month (low interest rate, owner occupied duplex I was house hacking). As I learned more I realized this was some of the cheapest money I could borrow and I was better off putting that extra money every month toward another purchase. I regretted making those extra payments and I always kinda figured that money was now trapped in equity. I never knew about the option to recast a loan so I just did the math and it looks like a recast would reduce my payments by $40/month. So for me it's definitely worth at least a call to the bank, if I can do it and there is no fee I just increased my cashflow by almost $500 a year.
So thanks @Scott Benton for sharing this information.