I suppose the downside is the complexity in circuit design. If the datasheet has a good reference schematic and instructions, or if you are good with electronic

I suppose the downside is the complexity in circuit design. If the datasheet has a good reference schematic and instructions, or if you are good with electronics fundamentals, it's not a big deal. If not... rolling the dice if it will work. These circuits have been one of the biggest sources of me having to respin boards. Requires a lot of attention to detail to get the passives correct in terms of values, net connections etc, compared to an LDO. Then you may go down rabbit holes like "The one at the switching frequency I want went out of stock. Can I use the one that switches slower? Can I substitute this capacitor in instead of the nonstandard value the ref diagram recommended?" They should IMO be the default for most designs, but double-check everything!