I have to agree, it doesn't look great, I arrange for boilers to be fitted in houses and to me. One of the most important finishes it the making good, ( plastering and outside brickwork) as that's what most people can see when we have patched up, I think if you spend a decent amount on something you should expect a nice finish throughout,
If you shortcut a little finishing what will you miss that can't be seen
My 2p