Flexible load resources are extremely useful for contingency reserve and peak shaving regardless. The nature of the generation fuel source and their proximity to a baseload generator is not as crucial as you claim. Most industrial processes cannot respond to system operator signals for load reduction and most really don't want too. So Bitcoin miners are filling an incredibly valuable niche.

If your point was that you can't operate a grid at 100% intermittent, then, of course you're right. But the amount of intermittent you can reliably connect is greatly increased with larger amounts of flexible load resources. There is a limit upper to the % of renewables for two reasons, forecasting renewables isn't perfect, and two, solar\wind are DC to AC invertered therefore intrinsically have no inertia. Low inertial systems have a greater frequency deviation slopes during a disturbance. Hydro Quebec does synthetic inertia on their wind farms from what I hear and that's awesome but I'm not certain it will ever be a full replacement for good old fashioned rotating turbine masses. My experience with these things is that you start to have reliability concerns when renewables make up more than 15-20% of your total capacity.

I do think people are trying to link renewables and Bitcoin mining are doing it for "green" propagandist reasons but its not exactly untrue either.

Note: I've doing grid operation for decades and spent several years on our regional balancing task force.