Why? I rather like it. I would probably never have owned it in the print version. I love that other works, like the Trésor de la Langue Française, which I could never afford, is now freely available online and available in CD-ROM for 69 euros (this was formerly over 1500 euros in print). I now also have Godefroy's Dictionnaire de l'Ancienne Langue Française on my hard drive (except for vol. 5, not available from the BN). Not only could I have enver afforded that one, but it was out of print.
In general, I think it's fantastic that public domain works are going online and non-public domain works are going online in accord with the publisher's and authors' wishes.
For all my complaint about putting copyrighted works online, I think that in the long term, getting materials online is a great thing. Most of the documents I work with exist in one place in the world with few or no copies. Increasingly these are being put online and suddenly historical research is freed from geography.