Hot take: tiny tile combos can be more satisfying than long words sometimes.
If you're just rearranging the two letters J and I, there are only two permutations to consider: 'ji' and 'ij'. In practical Scrabble play, the usable one you should care about is 'ji'. Most English word lists that include shorter foreign borrowings or romanizations accept 'ji' as a legitimate two-letter play; 'ij', which is a Dutch digraph, is almost never valid in English lists. That makes 'ji' the only real anagram you'd ever try to place on the board.
Beyond the bare fact of which permutation is legal, I like thinking about how useful 'ji' can be. J is a high-value tile, so playing 'ji' across a double- or triple-letter/word score can swing points. Also, 'ji' hooks nicely into a few common letters to build longer words—think adding a blank or an S to make 'jis' in casual games if your dictionary allows plurals, or using it as a bridge to form 'jib' and 'jig' if you can adjust tiles. In short, two letters, two permutations, and only 'ji' normally matters. I get a little giddy whenever I can squeeze a J into a short play and flip the score board, so that's my tiny celebration of the humble 'ji'.