Timing mark and cam tensioner covers?
 

Should I bother putting them back on? The only purpose they seem to serve is
a) letting me adjust/check base timing once every 3-4 years
b) making me skin my knuckles removing them

Do they serve some mythical function I am unaware of? I mostly reinstall them so that the 5 bolts holding them on don't become homeless.

Oh, new record for aligning timing marks and installing and tensioning timing belt- 20 seconds. I install the belt and tension it and check how far the timing is off and it happens to be perfect.