I need AnyDVD for one simple reason: Region locking.
Region locking was once important to Hollywood studios to prevent foreign consumers from viewing North American home video cassettes before the films completed their foreign theatrical runs, as it often took months or even years for a Hollywood film to officially reach the foreign market, delayed either by translation efforts, or the studios just being jerks and making the British wait longer. This was passively accomplished as a natural consequence of countries using different electrical currents and consequently utilizing different electronic signals, namely NTSC, PAL, and SECOM. Universal players that would convert the video to the correct signal were rare and pricey, not to mention that globalized commerce on a consumer level was uncommon, so it was difficult for typical consumers to circumvent the studios' release schedules.
In this modern digital age however, hardware's electronic signals are no longer a barrier to "incompatible" picture formats: All formats of a given medium, e.g. DVD, are fundamentally identical, with the only real difference being how many pixels are in a frame and how frequently to cycle to the next frame. A player that can play back both NTSC and PAL to an NTSC television is relatively easy to manufacture without having to gauge the consumer's wallet, not to mention that almost every home in first-world countries has a powerful personal computer capable of handling and displaying videos of virtually any digital format.
Therefore, the studios had to impose an active region lock in order to enforce their controlled distribution of home videos, and the vile DVD region lock was born, which then continued with the Blu-Ray region lock.
But do they really need to lock regions any more in this globalized economy? I remember years ago when one of the last Harry Potter films came out on home video, and the Region 3 Hong Kong DVD was released just a few days before the Region 1 North America release. Star Wars: The Force Awakens started playing in theaters on the SAME DAY in both North America and Japan, but you can bet the home videos will be region-locked.
Why this matters to me, while it probably doesn't matter to most other Americans:
1) Why must I limit myself to ONLY the films that Hollywood produces, and the small handful of foreign films that are half-heartedly imported, when there are literally THOUSANDS of excellent foreign films which will never be officially imported on Region 1 DVD or Region A Blu-ray? Instead the "foreign film" sections are flooded with cheap-to-import crap so boring that it makes watching paint dry exciting. The only alternative is to buy bootlegs off of eBay, which I have taken a great effort to avoid doing.
I have purchased several legitimate non-Region-1 DVDs and non-Region-A Blu-rays for films which have never seen an official North American release.
2) Languages is a hobby of mine. Watching foreign-language films is a fantastic way to help learn a language, and so is watching a familiar film, originally recorded in your mother tongue, dubbed in another language. If I were only interested in learning French and Spanish I could be quite content with North American DVDs (alternate audio tracks), but anybody wishing to listen to any other language is going to have a very small selection to choose from.
I have purchased several legitimate foreign DVDs and Blu-rays of American films so that I could watch them in alternate languages.
3) Being able to purchase from other markets gives me access to potentially superior versions not normally available to me. In an ideal world, all DVDs/Blu-rays would have the same content and special features, but in reality they don't. Sometimes one release has a poor digital transfer while another market's release is superb. One release will have just stereo while another will have other sound options. Sometimes the foreign interface is just better: A lot of my Japanese DVDs start the movie immediately without making me wait through unskippable copyright warnings, annoying advertisements, and stupid animated menus.
Yes, I am aware of region-free players and have a region-free Blu-ray player, but sometimes I want to watch a foreign movie while sitting at my computer desk. When I used to commute 100 miles and frequently worked late at the office, it was nice being able to watch a movie while I ate my dinner at my workdesk.