When you have a fit for partner and are not vulnerable, you have the luxury of making a "Fit Inspired Bid".
The purpose of such a "FIB" can be
Your partner opens 1♦ against vulnerable
opponents.
RHO overcalls 1♠.
You don't have the
semblance of a 2♥ free ON STRENGTH, but 2♥ might
discover a double fit in the red suits.
It might also convince the opponents not to bid 4♠ on hands
where it may make.
After 1♠-2♥-3NT, the favourable vulnerability argues in favour of a 4♥ bid. But why bid it directly ? By bidding 4♣ en route to 4♠ you can direct the lead in case your LHO bids 4♠.
LHO's game-forcing artificial 2♣ opening bid meets with 2♥ by your partner and a 3♥ cuebid by RHO. At equal or favourable vulnerability, bid 4♣. This may make it slightly more difficult for the opponents to find a Club fit, and may set up the defence against 6♠ or 7♠.
Look for opportunites to make these useful and descriptive Fit Inspired Bids.