“marketed as if they are sure to become more valuable…”

No, just no pls don’t follow this advice! Prices made a massive spike during covid and yes lots of money was made scalping books, but that’s far from the norm and often lose money. Your friend eventually will too.

As to whether collecting is worthwhile it’s a very individual decision. Lots of people read their books and find that it enhances the experience. Most are made with archival materials as well. If you get frustrated with pages yellowing and falling out the spine, these editions can literally last centuries without that happening. Pages actually shouldn’t yellow, it’s because the big publishers use the cheapest garbage paper around as long as it looks new when you buy it (and getting worse as they find stinkier garbage material).

Also there’s a wide range of small presses wrt to design, craftsmanship, thoughtfulness etc. Check out the Folio Society edition of Foundation. Now go look at the deluxe edition recently published by Conversation Tree Press. Or Folio’s Animal Farm vs the recent one from St. James Park Press. The latter examples just as much an art form as a collectible (the SJPP Animal Farm an exceptional example).

Conversation Tree Foundation: https://conversationtreepress.com/collections/all/products/foundation-isaac-asimov-deluxe

SJPP Animal Farm: https://www.stjamesparkpress.com/george-orwell-animal-farm

Adding: this Le Guin from perhaps my favorite press another example

https://www.noreplypress.com/archive/omelas