How high do transfer bids (to 1NT) go?
While the original idea for Jacoby transfers may have been to make the strong hand the declarer (in the 1950s, when Jacoby played with his wife, he bid naturally but she used transfers over partner's 1NT opening so that he would play more hands; this sort of agreement is no longer permitted), that is not their primary benefit.

The primary benefit of transfers is that it gives responder a second chance to make a call. Before transfers, responder to 1NT would bid 2H to play, and had to bid 3H game forcing; this left no room for invitational calls that also showed a major suit. Transfers allw responder to start describing many types of hands with a call at the 2 level, and free up 3-level bids to show other types of hands.

Combining 2-level (Jacoby) and 4-level (Texas) transfers, you can differentiate between the following types of hands:


5+ in a major with no desire to play a game (1NT-2D-2H-Pass).
Exactly 5 in a major with invitational values (1NT-2D-2H-2NT).
6+ in a major with invitational values (1NT-2D-2H-3H).
A balanced hand with a 5-card major and game forcing values (1NT-2D-2H-3NT; some pairs agree that this promises 5332 shape and others include some 5422 hands).
A more shapely hand with a 5-card major and game forcing values (e.g. 1NT-2D-2H-3C shows 5+ hearts and 4+ clubs).
A balanced hand with exactly 5 cards in a major and slam-invitational values (1NT-2D-2H-4NT).
6+ in a major with game forcing values but no interest in slam (1NT-4D-4H-Pass)
6+ in a major with slam interest (1NT-2D-2H-4H).
6+ in a major, asking for key cards (1NT-4D-4H-4NT).


These are just the basic agreements with Jacoby and Texas transfers; with some discussion with your partner, you can also ask for key cards after showing a 5-card suit, show shortness (either to avoid 3NT with a gaping hole or to find a 29-hcp slam when the hands fit well), and show other useful hands.

As for the example that you mention, the pair using Texas transfers got unlucky -- making the 1NT opener the declarer gains far more often than not from an opening lead perspective.