If you have high end audio equipment, the audio solutions on the high end motherboards can end up being a cheaper overall solution. For example, the headphones I use for gaming/music/movies/TV are the Sennheiser HD660S. These can't be driven well with bog standard audio found on normal £200 motherboards.
Jump up to £500 motherboards, Maximus Hero level, and you get a hardware amp, hardware USB DAC and fantastic noise isolation. I've tested this vs a standalone USB AMP/Dac solution (which was over £500 alone) and could not tell the difference.
Also if you need huge amounts of fast storage, the high end motherboards have you covered there. My Maximus Hero XIII system has 4 m.2 slots, while my Z690 Maximus Hero (which I'm still waiting to ship) has 5, including one PCI-EV5 slot ready for the gen 5 SSD's next year.
If you don't use high end audio or don't need lots of storage, then I fully agree the the £200-300 boards are far better value, and are mostly equal performance wise. This is especially true since Intel/AMD effectively removed almost all overclocking headroom from their most recent CPU generations, for normal ambient cooling methods.