It’s sort of more complicated than “gems are too expensive”.
It’s that if I use money to buy gems, there isn’t really anything I can immediately buy that makes me feel like it was a good purchase. I already have more sigils in events than I want to play. I don’t have enough time to chase leaderboards. I can’t use the gems to get chaos shards or deeds, the currencies I’d like to hoard. I can’t use the gems to reliably get the specific troops I need to complete mythic collections. I can’t use the gems to get pets. I can’t use the gems to make Delves easier outside of a time-limited faction event (where I don’t have the time.) I can’t use the gems to get tokens or medals. I can’t use gems to get a silly hat to put on my avatar or my troops. I can’t use gems to get a Horse Lord body pillow. I can’t use gems to get swimsuit art for Queen Grapplepot. I can’t even use gems to make my watch prettier.
So what exactly are gems for sale for? I can’t convert them into anything I want.
RE: Flash Offers, it really depends. All of the offers under $4.99 have been a good value. Some of the $4.99 ones were tempting. Like everything else in the shop, anything they valued at $10 or up felt like a bad deal. I’d love an Orb of Ascension, but I think it was in a $39 offer or some mess? I can buy entire games for that, so it doesn’t strike me as a great deal to spend it on something like 1/24 of a troop that’s 1/4 of a team that’s only slightly more powerful than the teams I already have.
The flash offers are extremely good deals.