It was a facetious comment since I can't for the life of me understand the reason why he gets to play 3min every other week. He's hardly subbed on to rest whoever is coming off since playing 88min or 92min doesn't matter from a fitness point of view and at the same time it can't be done to give VDB a chance to impact the game or show Ole what he's capable of either since it's barely enough time to get him on the ball once.
It would be one thing if the sub was made to slow the game down or waste time when we were leading, but it doesn't seem to matter what the score is or what kind of situation we're in, VDB gets his 3min no matter what even though everyone knows absolutely nothing comes from it.
It's just strange.
The answer is that he doesn't get to play 3 mins every other week. Donny has come on in the last 10 mins on 9 occasions, of which 4 fall into the category of substitutions that I don't understand (see below for more details).
Here are his substitute appearances in the PL this season: 23 mins, 1 min, 22 mins, 14 mins, 15 mins, 12 mins, 10 mins, 19 mins, 7 mins, 45 mins, 11 mins, 8 mins, 7 mins, 1 min, 3 mins
In CL: 2 mins, 11 mins, 45 mins
In EL: 5 mins, 45 mins
EFL Cup: 2 mins
21 sub appearances in total, 3 that lasted 45 mins, 2 x 20s, 7 between 10 and 19 mins, 9 late substitutions. Donny has been an unused sub in 15 PL matches and 2 EL games.
https://www.transfermarkt.co.uk/donny-van-de-beek/leistungsdaten/spieler/288255
Those 9 late substitutions: 2-1 win away at PSG - probably a combination of time-wasting and taking off exhausted players so as to improve our chances of defending the lead. A similar situation against Brighton with the score at 2-1 yet the match finished 3-2. In the 1-2 home loss to Sheff United, Donny came on for Tuanzebe after 83 mins. In the 2-1 home win over Brighton Donny came on after 82 mins with the score at 1-1. We scored one minute later. Similar in the 3-1 home win over Burnley.
That leaves 4 slightly weird late appearances (Granada away 5 mins, Man City EFL semi-final 0-2, Leeds away and Fulham home) that I can't see an obvious reason for. It could be that the player he came on for was exhausted. Perhaps Solskjaer views van de Beek as a better finisher than the other sub options available to him.
There are quite a few United players who have more than 10 sub appearances: Matic, Greenwood, McTominay, Pogba, Rashford, Cavani.
Looking at Dan James' stats, he is often an unused sub but has only made 7 sub appearances, of which 2 lasted less than 10 mins (PSG away 88 mins, Villa home 87 mins). Juan Mata has a similar pattern of often being an unused sub but only rarely getting sub appearances, though 4 out of his 7 sub appearances lasted less than 10 mins. So perhaps Donny is preferable to using Dan James or Mata in the last 10 mins.