With a good descriptive one diamond bid followed by a good descriptive one spade bid what is the point of opening one notrump resulting in notrump being played from the wrong side or burying the diamond suit?
Opening one notrump here when other reasonable alternatives are available just suggests you ...
Give partner a perfect working 14 count such as:
S Axxx H AQxx D x C Axxx
and your side can't make six spades.
Give partner a little less such as:
S Axxx H Axxx D x C Kxxx
and five spades is in danger of going down.
I like being able to play 5H where the opponents need to find a trump lead to set 5H where partner has say:
S x H AKJxxxxx D x C xxx
rather than defend 4S and pray partner has a diamond stiff. Further, if the opponents bid one more surely ...