If I'm ordering it at work it's because I'm at work and can't pick it up myself. I sometimes do that for lunch when I'm working overtime to treat myself. If I'm ordering it at home it's usually because I'm indesposed in some way. In both situations picking the stuff up myself wasn't a feasable option but I still wanted the stuff enough that I was willing to pay more for it.

For example I'm pretty sure I currently have RSV so last night I door dashed some food from one of my favorite resturants and doubledashed a pharmacy for some pedialyte and cold medicine. I could have gone out to grab the stuff myself but I would have potentially infected everyone I came in contact with. By going through a delivery service I didn't risk infecting anyone and I didn't have to drag my miserable snot laden wheezing self out of the house.

I've also only ever personally had one quality issue with door dash which wasn't that major anyways. Otherwise everything has always arrived perfectly fine.