Need-based awarded mean that one party cannot afford the fees and that the other party has the means to pay. In many cases this can be a problem as neither party can really afford additional fees. Conduct-based fees are awarded when the court finds a party to be acting in bad faith and unreasonably contributing to the length or expense of the proceeding. As frustrating as the process can be, that does not necessarily mean the court will award conduct-based fees. And even if there is an award, that does not mean the other party will pay it. The expectation for many attorneys (myself included) is that my client will pay my fees. I am not interested in chasing down the other party for payment. If the other side happens to pay for what my client has already paid for, than that money will be passed along to my client, but I don't wait for the other side to decide to pay me.
There is also the practical problem that getting an award for attorney fees means that you have gone through the court process and are now in front of a Judge asking for a decision. If you are going to court on other issues, then it may make sense to ask for attorney fees. But, it does not make any sense to incur additional fees just for the possibility that the court will grant an award. In most cases, parties agree to each pay their own attorney, but the issue of attorney fees can be a discussion of negotiation and sometimes the parties will agree to a contribution for fees, or will offset fees in the property division.