The last manual I bought was the Hornady 7th (I believe...) for the .348WCF and Service Rifle data, specifically.
I have used online data but would rather just have it in a manual sitting in front of me. Just old school.
There is something to this... the quickness and availability of instant reference data... my own version of 'bang, flop' ... that is, the spine of the manual hitting the bench, and flopping open. I often reference not only load data, but OAL and trim data, etc. I have tabs on my books for the cartridges I load for, and I can have a look-see in about 5 seconds, vs going to the computer, pulling up a website, looking at what I want... and usually getting distracted... (skwerrel!)
When I started loading for the 6.5CM, none of my manuals had data for that... so I had to source it online. I can see where, assuming you are an experienced reloader, you would not really need the reference of a physical manual... in my case, the 6.5CM data is right from the bullet maker, or the powder seller, online, there is not much ambiguity. I could see, however, for a newer reloader, getting into rifle cartridges, for example, where a good manual... and up-to-date manual... would be worthwhile. I could also see where something like a Lyman manual would be handy for esoteric data... cast bullets in the .30-06, for example, where a bullet manufacturer's manual may not have something like that, or with a wildcat cartridge.
It really boils down to individual needs.