Southwest Rapid Rewards is offering a 40% bonus on purchased miles through the end of the month.
The price of to buy points with this offer is 1.96 cents apiece. At most Rapid Rewards points are worth 1.42 cents (plus some option value in that Southwest award tickets are cancellable without penalty).
Don’t buy speculatively, even revenue-based programs can devalue.
The only reason to take up this offer would be if you had a very specific award you needed a small number of points to redeem for. Even then recognize the more you buy, the less value you’re getting for your redemption since every mile purchased loses over half a cent.
Points.com processes Southwest points purchases so they do not earn airline purchase bonuses that your credit card may offer.