Purchasing miles/points CAN offer good value but you must first decide on your own personal valuation of each mile/point. Only then can you decide if it’s worth it.
at the extreme end of the spectrum, a night at St Regis villa in the Maldives might cost $2,000 per night or 85,000 points. Even without a single point to begin you could purchase those points with a 50% bonus for $712 making a huge saving per night.