There was a time where we search chrome and look for a online video downloader to download youtube videos which sometimes work sometimes doesn’t and also consumes lot of data during that time not everyone has unlimited data so people used to download videos and watch it offline whenever needed.
That time it came as a blessing in our lives atleast in my locality everyone who has youtube was using snaptube with it. It offers a lot of features which were later introduced by YouTube like Popup video player, Video Download in any quality you want, Downloading videos as audio file, and some features that youtube will never introduce it for free like ads free experience.
Overall a great app of that time now you have so many apps that took inspiration from this and are doing well now.