^^^This. I honestly cannot tell whether any of the "technical fabric" garments I own -- whether they are base layers, top layers, mid layers, whatever... -- do what they purport to do. So I just wear the ones I find are comfortable.

In hot whether, that usually means no base layer at all.
On a day when the temps will start cool and get hot (or vice-versa) I'd rather have the base layer than not. Also because. all else being equal, a base layer prevents irritation from bib straps.

But I couldn't tell you whether my Merino wool base layers are any better at wicking moisture away from the skin than my polyester or polypropylene base layers. :shrugs: