Are There Any Good Reasons NOT to Be Just "Friends First" when Starting a New Relationship?

With regards to the idea of being just "Friends First" in any relationship between two people whose relational intentions are a long-term, happy, loving, successful and harmonious relationship, can you think of any possible reason NOT to be just friends first or any possible reason why being just friends first could be a bad idea?

I suppose in order to acknowledge anything bad that could arise from this relational ideal, maybe it would be a good idea to consider some of the positive aspects of it. Here are some of the positive things I've quickly come up with:

-You get the opportunity to establish a meaningful "Like" for each other. How many times have we seen people say, "I LOVE my spouse, but I don't LIKE them anymore"?

-You get to learn about each other's convictions, religious/spiritual beliefs and political views and judge how well in sync you are with each other in this regard without thinking you have to "tolerate" something you don't like for fear it might disrupt your MARRIAGE.

-You get to establish an understanding of each other's lifestyles as "Individuals" without having to make quick and uncomfortable compromises after you've moved into the same home too quickly without really knowing whether or not you're truly compatible with each other.

-You get to test your relational chemistry by advancing slowly. This gives both of you a "choice" in backing off when something happens that you're not comfortable with. If you're already "married", backing off often means pricy divorces and other long term financial strains.

-You get to become acquainted with each other's personality quirks. It's my understanding that such quirks can help solidify, strengthen or deepen some peoples' attraction to each other while for other people, it can attribute to growing distaste and/or resentment of each other.

-It gives you plenty of time to discuss how you might handle money and other financial matters. "Financial Issues" are often an aggravator towards divorce.