Since fewer people are using these dictionaries, fewer people are using the definitions and translations they give. Does it follow that these dictionaries are, nowadays, not as helpful as those widely used on the Internet?
Esperanto is not static, but it is very stable, partly on account of the Fundamento and the continued currency of the earliest texts, and partly because its users are relatively conservative and (for obvious reasons) hesitant to invent slang. From time to time a word or expression will fall out of favour because of problems it causes, and be marked evitinda in newer reference works. But this does not happen frequently enough for us to think that printed dictionaries are obsolete.
The one part of Esperanto vocabulary that does need extra care is technical jargon. Some words related to newer devices and machines have not been firmly established, and the choices made in Wikipedia, for example, can turn out to be problematic. So I'd suggest always cross-checking all the most up-to-date sources for anything of that kind.
A language is not defined by beginners. Esperanto is an established language with a long tradition. Many of these dictionaries represent a very large amount of scholarly work by people with impressive credentials.
I think Lee Miller put it very well in his comment on the question. (Quoted with permission.)
Vortaro.net is the text of the printed PIV2005, so it is essentially equivalent to the physical dictionary. Reta Vortaro is based on the Plena Vortaro, and is useful in many ways. I'm not sure it should be regarded as authoritative. ESPDIC aims specifically to document all usages of words in Esperanto, whether they're good or bad. I have significant hesitation about recommending it as a reference for people learning Esperanto. The fact that fewer people are using print dictionaries like Wells (which is available, by the way, via Google books) in no way makes them less good.