It sounds like a good idea, if only to reduce the volume of repetitious material being duplicated across the InterWebs.

This is also the minimum cost solution for Gog.

It adds an extra step in the process, which creates an implicit agreement from the customer that they are okay with seeing whatever is on the other side of the hyperlink.

Problem solved.

(Yes, there is a cost; no longer will the mailout have pictures that we might easily identify the game. But there is no need to be as restrictive with other aspects, like the description.)

Because a number of online sites (unlike an irl locale like an alley, which might be someone's only way to/from some needed destination) can easily be avoided, especially if it's something less necessary for living like a games store.

Would be a nice compromise, but let's be honest: a select few would likely still complain about "lewd adult text" in their emails. So then where do the compromises end? If i've learned anything over the course of my life, it's that a number of (oft easily offended and overly entitled) humans want the world to conform to their every demand, no matter how small or inane. At this point, i'm in the "let them adapt or avoid things they dislike" camp.

QFT

The same reason why you don't have picture-less advertisements for any visual medium entertainment: it's not effective use of advertising.

Even food has pictures in a sales catalogue. And, yes, pictures of raw steaks or a roasted chicken are likely to horrify and offend some Vegans (or people of certain phobias) for example but we still advertise food the same way and don't cry out to have pictures banned from advertising there.

Food for thought (no pun intended, but it is rather cute) that of all the imagery which could offend it's primarily sex and nudity (even if suggested rather than actually shown) which is the most complained about and action demanded over.

It's too hard to have a text-only default email marketing push stream?
So let's just decide between a total ban or anything goes?
Excluded middle, via a slippery slope, to a strawman? Fallacies everywhere!

Surely the text email is a simple, effective way for customers to self-organize?

Just as one used to have to go behind a (literal) curtain in the VHS-era video rental stores to peruse the X-rated titles, so too anyone who wants to can select the full, glorious graphical experience — perhaps even with an extra-high quality option? Would not that be better? Maybe with AI-enhanced imagery?
On the radio? ;P
Restraint and respect will also garner popularity, at least amongst customers like me. (: