All fourteen Pis, even v4s (which are significantly hungrier), would be lower power (as in electrical draw) than even a feeble (as in compute power) traditional machine.

If you can distribute your workload (or it's not intensive anyway), i.e. having no single machine with a faster processor, then I think it's a good choice, cheaper to run.

Edit: I'm happy to be corrected if down-voters would like to reply... A Pi 4 draws 6-7W at full load. A former desktop PC turned server likely idles over 100W.

They're different beasts, so I'm not saying 'a Pi is better than a PC', I'm saying 'if your load could also be handled by a (bunch of) Pi(s), then all else being equal that might be better than the PC'. Of course all else is never equal, ymmv, you may already have the old PC, you may need very many Pis, so even if pennies cheaper to run it might take years and years to break even on the Pi acquisition cost.