Housing stock is a huge thing. As an expat, working remote, and (legally) living here, the locals can't believe how much I spend on rent, which is still cheaper than I was paying in the states, but far more than any native could/would pay.
The country is likely missing out on (pretty substantial) income taxes, so through legalization they are trying to get some of that. I'm sure the countries enjoy the injection of cash into their economy, but they would rather get that from tourists vs. people working, who tend to use more public resources than tourists.
I'm not seeing how digital nomads have an additional negative impact compared to tourists though. If we're comparing not having wealthy foreigners vs having them, then yes, nobody will deny that has an effect on housing stock, but having digital nomads vs tourists is either a wash or a benefit to the digital nomads.
As for public resources, people who commute for work most likely use more than tourists, but digital nomads doing so would be an outlier.
The differentiation between digital nomads (people on a tourist visa/waiver) vs expats is an important one, as expats do get more entitlements to public services due to their legal residence.
The country is likely missing out on (pretty substantial) income taxes, so through legalization they are trying to get some of that. I'm sure the countries enjoy the injection of cash into their economy, but they would rather get that from tourists vs. people working, who tend to use more public resources than tourists.