403b and 457b plans

If a client can contribute to both a 403b and 457b plan, my understanding is that they can effectively contribute 2x the normal limit (i.e. $47k instead of $23.5k under age 50).

If said client doesn't have the cash flow to contribute that much and is going to stay under the $23.5k limit anyway, is there any reason to split the funds between the two plans? My inclination is to keep it simple and just use the 403b.