A strumming pattern is a technique for playing a rhythmic pattern. Most simple rhythms are best played with the strumming pattern you describe because this is the best way to keep your rhythm accurate.
As for picking patterns, it is not silly at all. It is crucial that you learn the most mechanically efficient way to execute sequences.
Single string: Sequences where many notes are played on the same, repeated string are best played with alternate picking, which is a strict down-up pattern (or sometimes up-down).
Crossing strings: Sequences like arpeggios which are on three or more consecutive strings (either up or down) are best played with sweep picking because you don't need to reverse the pick's direction to continue onward and strike a new note.
Complicated patterns: string skipping will help you to play complicated patterns that leap over many strings. The picking direction of string skipping is often alternate picking but it really depends.
Combinations: Many combinations of the above two are best achieved by economy picking which basically means that the picking pattern will be alternate picking when the notes on a string are repeated and sweep picking when changing to a new string.
I think if you're seeing alot of information about "play this thing with that picking pattern", it may be confusing you and you may have trouble seeing the forest from the trees. But you need to master the basic mechanics of picking, and most passages definitely have a mechanically ideal pattern that should be considered. Advanced guitar players know these patterns, and if you choose a pattern other than the most mechanically efficient one, you're making it harder on yourself than an advanced guitar player would make on himself.